Jeffrey Sandusky Requested 'Pee' Pics of Underage Victim ... Cops Say

Jeffrey Sandusky allegedly texted his underage accuser asking for naked photos and shots of her "taking a piss" ... this according to the police report obtained by TMZ Sports.

The report mentions 2 accusers (referred to as "Victim #1" and "Victim #2") who are sisters. Sandusky was dating their mother.

Victim #1 claims in 2016, Sandusky made several secret inappropriate sexual advances toward her -- many of them over text message.

She claims in the report Sandusky asked for pictures of her "boobs" and explained "it's not weird because he studied medicine."

Also in the report, she claims Sandusky also asked for her to send photos of her "in the morning when she is dressing for school" and also "while she is changing or taking a 'piss,' etc."

Victim #1 told police she informed her mother about the incidents months later and she threw Sandusky out of the house. Victim #1 claims Sandusky apologized and said he knew his actions were wrong.

Victim #1 claims she told her older sister who said Sandusky had been texting her similar stuff back in 2013 and asked her for oral sex. The police report says Victim #2 claims she did have sexual intercourse with Sandusky when she was 15 and he was 37.

Victim #1 claims her sister was furious when she found out about Sandusky's alleged behavior and "tore into him." She claims he tried to explain his way out of it.