BELFAST, Maine — Last week, a woman finishing a walk on the cross-country trails behind the Troy Howard Middle School was shocked to spot a man engaging in a solo sex act in his Jeep in the parking lot there.

Her concerned call to the school district eventually helped police track down the man, who did confess to the act. But now officials are hoping to track down the woman, who did not leave her name and who was the sole reported witness to the man’s lewd conduct.

“We want the community at large to know we have, through video surveillance technology, determined who our suspect is. However, we don’t know who our complainant is,” Chief Mike McFadden of the Belfast Police Department said Tuesday. “We need this lady to give us the call. She’s the witness. Without her, we can’t go any further.”

The woman called the school district to report what she saw at about 2 p.m. on Wednesday, Aug. 29. She said that as she emerged from the footpath and crossed the field hockey and softball fields, she noticed the Jeep, with the man inside it. Although no students were using the fields at that time, McFadden said that the field hockey team missed the incident by about 20 minutes.

“If anybody happens to run into an unfortunate situation like this, please call police,” the chief said. “This is very definitely a police issue.”

To reach the Belfast Police Department, please call 338-2420.