Three armed robberies have police and residents edgy about bicycling thugs in Fairmount.

Ninth District police officers are warning Fairmount residents to keep an eye out for a team of armed bicyclists who've robbed at least three people this month.

With memories of last spring's brick attacks in nearby Northern Liberties still fresh in residents' minds, the message to stay alert has resonated — to a point. Some locals say some cases have gone unreported, meaning the three attacks may not depict the full picture. Considering that many others hadn't heard of the attacks when asked about them this week, police say they want residents to be alert.

"We've been aware of this problem from the beginning and we've stepped up our deployment numbers in the areas that these guys have been in," says 9th District Capt. Dennis Cullen whose area covers Fairmount and Center City to the west of Broad Street. "In this day and age people don't think twice about a bike being ridden past them on the street or the sidewalk [but] we need more people to be alert to who's riding these bikes through their neighborhood and where they're going."

Cullen says the bandits have used the element of surprise to their advantage, much like they have in other parts of the city where police consider robbers on two wheels a law-breaking trend. He said earlier this week that the suspects remain at large.

In Fairmount, they've targeted victims who are either walking alone or in small groups between 10 p.m. and 2 a.m. The typical modus operandi involves a bicyclist riding up to someone when they're not paying attention and brandishing a gun before their mark knows what's going on. The incidents have occurred on Fairmount Avenue and Mt. Vernon and Parrish streets.

One victim, a 20-something female whose name is being withheld, told police that she and three friends were leaving a home on the 2200 block of Mt. Vernon Street around 9:30 p.m. on Aug. 8. Though she planned to go out and celebrate a friend's birthday, the victim would instead spend the evening poring over mug shots.

She reported that a 5-foot-8-inch clean-shaven black man in his late teens or early 20s with short hair and a slender build rode up on a yellow BMX-style bicycle and calmly said, "Nobody go anywhere." He then pulled out a gun, held it to the back of her head and demanded money.

"At first, I was in total shock and really thought it was some kind of joke," says the woman. "All I could feel was the gun on my head and I'm thinking he's gonna go after my [engagement ring]."

The assailant, who had one accomplice that rode up the street as a lookout and another who sat nearby on his bike, made off with a paltry $20. Luckily, the victim says, she told her fiance not to stop at an ATM before meeting them.

As the sounds of a woman screaming for police isn't common on that block in the shadows of state Sen. Vincent Fumo's manse, at least five neighbors immediately called 911. Officers arrived within 10 minutes and drove the victim around the neighborhood hoping she would see her assailants. She didn't.

"We haven't had an incident in 10 or 11 days and we've made some arrests in the area," says Cullen. "They don't seem to be connected, but there's a possibility."

When a major crime occurs in Fairmount, it tends to get some publicity as it's not an everyday occurrence. By the numbers, the 9th District is among the lowest when it comes to murders, rapes and robberies. As such, many locals remember the July 2000 rape of a 40-something woman in her Ringgold Street home. She jumped out of a second-story window to escape her attacker. In that situation, composite sketches were posted throughout the neighborhood. Police haven't taken that step in these cases and though there hasn't been a substantially noticeable increase in patrols in some parts of the neighborhood, a group of residents near 22nd and Mt. Vernon recently said they thought police were "using a lot of undercover cops on the streets as a tactic to catch these guys."

Derek Mason, who works at Tavern on the Green, says he's been urging some patrons to call a cab rather than walk home.

"These hustles don't surprise me around here. Hard-up guys find a lot of opportunities to jack people," says Mason, who's noticed that many customers have stopped carry cash. "It's a shame people are going out and they're paying with credit cards and someone approaches them with a gun and they don't have any cash so they get jacked, which is a traumatic thing, for just about no reason."