Oakland police released a sketch Wednesday of a man they say may be responsible for touching two girls inappropriately at schools in the city’s Fruitvale District over the past two months.

The first incident happened about 4 p.m. Jan. 24 when a 6-year-old girl was touched by a stranger on the campus of Think College Now Elementary School at 2825 International Blvd., said Officer Johnna Watson, an Oakland police spokeswoman.

The man asked the girl to sit on his lap, which she did, before she felt uncomfortable, left and notified an adult, said Sue Piper, a spokeswoman for the Oakland Unified School District.

About 4:10 p.m. Friday, a 7-year-old girl reported being touched by a stranger at the World Academy, an independent charter school at 1700 28th Ave. The girl alerted an adult, and the school initiated a lockdown on its own and notified police.

The man is described as white or Latino, 20 to 40 years old, 6 feet tall, weighing 180 to 200 pounds, with black hair and a mustache. The man may have a rash or birthmark on the left side of his forehead.

Crime Stoppers of Oakland is offering a reward of up to $ 7,500 for information leading to an arrest in this case. Anyone with information is asked to contact the Oakland police Youth and Family Services Division at (510) 238-3641, a tip line at (510) 637-0298 or Crime Stoppers of Oakland at (510) 777-8572.