'American Idol's Caleb Flynn Placed in Solitary Confinement After Wife's Murder

"American Idol" alum Caleb Flynn must be singing the blues behind bars ... TMZ has learned Caleb has been placed in solitary confinement after he was locked up for allegedly murdering his wife in Ohio.

In mid-February, Caleb was arrested for allegedly shooting his wife Ashley to death in their bedroom at their Tipp City home while their children slept in another room, according to police. Caleb called 911 to report an intruder broke in and shot Ashley.

Prosecutors charged Caleb with murder, felonious assault, and tampering with evidence for allegedly staging the crime scene. Caleb was booked into the Miami County jail on $2 million bail.

TMZ spoke with a veteran corrections officer at the jail who tells us ... Caleb was placed in a single cell in isolation to ensure his safety as he awaits trial.

We're told other inmates have been asking staff about Caleb ... but correctional officers won't let them interact with the high-profile inmate due to security concerns.

But, Caleb isn't without his perks in the pokey. The officer tells us Caleb has access to a tablet that he can use to make phone calls, watch movies (with no nudity), and read letters scanned in from another facility that receives mail for inmates.

Our source also tells us Caleb is allowed to shower once a day -- maybe twice if necessary -- and gets 5 hours of recreation per week. We're told officers escort Caleb to an outside rec area on the jail's grounds so he can breathe fresh hair and walk around in a circle.

The officer goes on to say Caleb is monitored around the clock by staff and cameras ... and staff even checks on him every 30 minutes to make sure he's alright. We're also told Caleb eats three squares a day inside his cell, alone, and is allowed video visitation with family.