FORT WORTH, Texas -- A bizarre attack along a popular recreational trail has rattled joggers and walkers in Fort Worth.

A woman jogging on the Trinity Trails was assaulted by a naked man in broad daylight, police say.

It happened Saturday evening just after 6. She was jogging when she spotted the naked man near a low-water crossing.

"She ran the other way, the male was on a bike, he was able to catch up to her," said Officer Tracy Carter with Fort Worth police.

He took her cell phone and threw it in the Trinity River. Police say that he assaulted her before she was able to escape and run to a neighborhood to call 911.

Police say the woman is okay at this time, but they're investigating a possible sexual assault. They're asking for the public's help to locate a young man, 18-22, with brown hair and no body hair.

The attack happened not far from the Press Cafe and the Clearfork outdoor mall, home to Neimann Marcus and other high-end stores.

The man had been seen a half-hour earlier downstream, riding a bike, and sitting naked on a bench near The Woodshed, a popular restaurant. Police responded to a call reporting him, but they couldn't locate him. They were called about the attack minutes later.

There have been concerns about safety along the Trinity Trails before. Last December, two young women were attacked by a man who was later arrested. One woman got away, but a second was assaulted and lost a tooth. Police believe two of the attacks were conducted by the same suspect.

In April, Fort Worth police unveiled a new dirt bike fleet donated to help patrol the trail system. But Fort Worth police said they were likely not in use Saturday evening. They said some officers certified on dirt bikes were deployed to Houston following Harvey, while others are still being trained.

Police said there are traditional bike and vehicle patrols along the trails, and they are stepping up patrols in response to the attack.

Still, many people who use the trails said they've not seen a police presence. Dany and Fred Hernandez moved to Fort Worth two months ago and walk the trails everyday, but they said they've never seen an officer.

"There are some parts around here that are kind of vast," said Fred Hernandez. "It has made us wonder why there isn't any kind of patrol, cameras, any kind of security that we can pick up."

In a city that cherishes its running culture, it would make sense that a store, devoted to training runners, sits just yards away from the Trinity Trails.

“It’s the first place we tell people to run if they’re in from out of town, here on business—where should I run? The trail,” says Cory Eilers, manager of the Fort Worth Running Company.

It’s where the Running Company sends its own running clubs, too. But news of yet another attack on the trails—this one especially heinous—is shaking them hard.

Runner Karen Atavales says she never runs alone.

“No, never. Because I feel scared,” she says.

The Fort Worth Running Company is urging its runners to go out in pairs, especially considering the suspect hasn’t been caught.

“Fear is certainly is one of the first words,” Eilers says.

And it’s not a word they want to associate with running.