OKLAHOMA CITY - Oklahoma City police arrested a 17 year old accused of befriending then sexually assaulting a 9-year-old boy.

According to the police report, the victim sat down to have dinner with his grandmother on June 24. He suddenly told her he needed to write a note. The victim wrote on a piece of paper that Eric Mardis had sexually abused him, followed by a sad face. The boy's grandmother immediately called the child's mother, who called police.

The boy's mother told police Mardis began hanging around her son about a year ago and acting like a "big brother" to him. She also said the boy had recently experienced behavioral problems, so she bought him a note pad so he could write down his feelings instead of acting out and getting into trouble. He used the note pad to tell his grandmother about the alleged abuse.

It's not clear how long the abuse had been going on, but the boy's behavioral problems began a few months ago.

The victim told his mother Mardis would abuse him when the boy spent the night at his house, or when the two took the dog for a walk. Police arrested Mardis and booked him into the Oklahoma County jail on suspicion of lewd acts with a child.