He was brazen and then he was gone.

But two years after a string of disturbing sightings of a naked, masked man in London's north end came to an abrupt end, a new incident has residents and police wondering if he's back and as bold as ever.

A woman reported seeing a nude, masturbating man -- decked out bizarrely in a decorative mask -- while she sat reading Monday evening at Elsie Perrin-Williams Estate, a beautiful park near the University of Western Ontario.

"That guy's been running around here for four or five years," said Bill Rosborough, who lives just inside the estate's entry gates.

Rosborough was recalling a number of similar sightings by women two years ago that peaked when a man tried to remove a sunbather's bikini near Windermere and Western roads.

London police at the time figured the same man, who wasn't caught, was involved in an estimated 10 incidents.

Though there's no evidence linking those crimes with Monday's run-in, police haven't ruled that out, Const. Joel Pavoni said.

Shortly after 5 p.m., a woman was reading a magazine when she saw the nude man fondling himself at the edge of a wooded area, police said. The man then ran into the woods.

The woman offered a vague physical description of a white man, standing about five-foot-eight and weighing 160 pounds. But she also described his "decorative" red-and-white mask, which looked more like art than a costume.

"(It's) not something that you'd buy in a novelty store," Pavoni said, adding police didn't have a sketch to release.

Anyone involved in a future incident should do exactly as this witness did on Monday, Pavoni added.

"We never recommend approaching him," he said. "She did the right thing -- call police, we'll search the area and do our best to find him."

Elsie Perrin-Williams Estate, a park surrounded by UWO's campus and several high-end homes, is an otherwise quiet area filled with pedestrians throughout the summer, said Rosborough, who offered a caution to women visiting alone.

"We have a lot of people walking through here with dogs, especially women, so they've got to be careful," he said yesterday.

"It's nice that the city has this spot . . . it's nice to walk through the property, but be very, very careful. This guy's obviously sick in the head."

Anyone with information is asked to call Crime Stoppers at 519-661-5670.