Sources connected to the case tell us ... prosecutors say the officer who made the observation is a star witness who is one of the most authoritative people in the area on DUI -- and an unimpeachable witness.
There's another hole in the case. Cops claimed Justin was drag racing, yet we've obtained the GPS read on his car and it actually shows in the middle of the so-called drag race he was going 27 MPH -- UNDER the 30 MPH speed limit.
Our sources say they're not buying the GPS read out and they have their own GPS which they believe will show a higher rate of speed.
Bottom line -- sources connected with the case are confident ... this case will NEVER go to trial because Justin was driving under the influence of marijuana and Xanax. They are virtually certain Justin will take a deal.
The Justin Bieber toxicology report from his DUI arrestin Miami Beach is in ... and it shows he tested positive for marijuana and prescription medication, TMZ has learned.
According to the report -- obtained by TMZ -- Justin's urine was tested right after he was busted for driving under the influence on January 23 ... and it shows there was THC and Alprazolam in his system.
FYI -- Alprazolam is the key ingredient in Xanax (prescription anti-anxiety medication).
The report also shows Justin tested NEGATIVE for cocaine, opiates, meth and other drugs.
According to the docs, a cop at the scene claimed Bieber "reeked of marijuana." Cops say Bieber's reaction was this ... "Yeah, we were smoking all night at the studio."
The officer claims Bieber was initially open to taking a "breath test" but then had a change of heart, asking the cop what would happen to his license if he refused the test.
The cops say Justin was out of it and couldn't follow basic instructions on how to provide the breath sample. The docs say "he had extreme difficulty providing a continuous breath."
The report also says Bieber wasn't blowing into the tube properly and cops thought he was deliberately undermining the test. Bieber then became "agitated" and told the officer he was "blowing into thehose like he blows into his trumpet."
Cops say he admitted he took medications for anxiety, saying "My mom takes care of all that stuff for me."
Justin Bieber's trail of destruction continues -- TMZ has learned, the singer just took a $5,000 hit ... after hotboxing the Miami mansion he rented and riddling the joint with marijuana smoke.
Sources close to the cleaners tell us ... Bieber rented the 5-bedroom home for 7 days through a website called CarefreeLifestyle.com ... and smoked so much weed in the house with his friends, the place stunk to holy hell.
We're told Bieber paid $4,200 a night for the place from January 18 to January 25. He also plunked down a $20,000 security deposit.
We're told Bieber only got around $15,000 back ... because the cleaners estimate it will cost around $5k to make the house livable again.
Justin Bieber is suffering from the same delusion that Michael Jackson once embraced -- putting on a false air of confidence when behind the scenes their lives are falling apart.
You'll recall the scene with MJ back in 2004 ... after his arraignment on child molestation charges. Michael famously jumped on his SUV and waived and smiled, trying to convince everyone things were ok.
Justin Bieber's people are asking the singer to come back to L.A. so they can sit with him and convince him to go into therapy ... IMMEDIATELY.
Sources connected with Bieber tell us ... they have been trying to get him into rehabfor months, but he has scoffed at the idea -- he won't have a conversation about it and insists he doesn't need it.
So we're told his people believe the next best step is psychotherapy ... to deal with both his drug problemand the underlying issues that have caused it. We're told Justin has not rejected the notion of therapy and is willing to have the discussion when he returns to L.A.
Justin's team have played armchair shrink over the last year, and they believe the root problems involve his upbringing as well as the obvious -- being a child star who grew up rich and famous and got a little too used to it.
Justin's people are hoping that a judge might order him into rehab ... but the reality is that probably won't happen because the Miami offenses are not that serious. On the other hand, if the egging case is filed as a felony, it's possible rehab could be part of a plea deal.
Justin Bieber just ratted on one of his drug suppliers to police -- telling cops, HIS MOM is the one who gave him the prescription medication he took shortly before his DUI arrest.
Law enforcement sources tell TMZ, cops grilled Bieber on what substances he had ingested before his arrest ... and the singer admitted he was under the influence of Rx meds, alcohol, and weed.
When asked what kind of Rx meds, we're told Bieber said anti-anxiety (such as Xanax) but he wasn't sure exactly what kind ... because he just takes whatever his mom Pattie gives him.
It's unclear if he has his own prescriptions for the drugs -- and his mom just handles them -- or if he's using his mom's prescriptions ... which would be illegal. If Bieber does have a valid prescription , the presence of the substance in his system probably won't be held against him.
As we reported, when police raided Bieber's house following the infamous egg attack, they found Xanax pills in the home ... so it all syncs up.
11:36 AM PT -- Justin left the jail just moments ago ... climbing on top of an SUV and waving to a crowd of fans.
Justin Bieber was arrested for DUI early Thursday morning and it wasn't pretty -- cops say Justin was wasted and resisted arrest and cussed the cop out, dropping multiple F bombs ... TMZ has learned.
Justin posed for a smiley mug shot moments after the arrest -- while sporting a jail-issued orange jumpsuit.
Law enforcement tells us ... Bieber was busted in Miami Beach and it didn't end with DUI ... he was also busted for resisting arrest without violence, drag racing and driving on an expired license.
Law enforcement sources tell TMZ ... they believe Justin was under the influence of both drugs and alcohol.
We're told ... Justin blew a .04. That would not automatically make him a drunk driver -- IF he were 21 or older. But Justin is 19, and Florida has a zero tolerance for underage drinkers who drive. A BAC higher than .02 is ground for an automatic license suspension.
In fact, officials held a news conference and said, "[Justin] made statements he had consumed some alcohol, been smoking marijuana and consumed some prescription medication."
According to the police report -- obtained by TMZ -- cops approached Bieber's car and they instantly realized he reeked of alcohol and had bloodshot eyes. He had a "stupor" look on his face.
The police report says ... Bieber was defiant from the get-go, yelling at the cops, "Why the f**k are you doing this?" He also yelled, "What the f**k did I do. Why did you stop me?"
When the officer tried to perform a routine pat down, Bieber said, "I ain't got no f**king weapons, why do you have to search me? What the f**k is this about?" Bieber claimed he wasn't drunk and coming back from recording music. That's not true, because we knew he was at a club.
Now the basis for the resisting arrest charge -- Before the pat down, as Bieber got out of the car, he "kept going into his pants pocket." The cop ordered him to put his hands on the vehicle, and Bieber initially complied but soon took his hands off the car, turned and then cussed out the cop. The cop then grabbed Justin by the right arm, Justin pulled his arm away, and said, "What the f**k are you doing?"
The report says Justin was driving between 55 and 60 MPH in a 30 MPH residential area.
Bieber was taken into custody and transported to the police department where his blood alcohol level was tested. Our law enforcement sources say Justin was given a field sobriety test at the scene ... and failed.
His was then taken to jail where he was booked and processed.
We're told Bieber had just left SET nightclub and was driving a yellow Lamborghini at the time cops spotted him in a residential neighborhood. Our sources say Justin's people actually blocked the street off so Bieber could drag race.
Sources say the person Justin was racing was also arrested. We're told that driver was Khalil, a well-known rapper on Def Jam Records. He was in a red Ferrari.