Since the beginning of July, law enforcement officials said, at least nine women have had their handbags snatched on the streets of the Upper East Side. In many of the cases the thieves fled on bicycles.

A woman named Susan, who lives in the East 90s, said she was the victim in one of the recent cases of grand larceny. She told The New York Sun her story on condition that only her first name be used.

On August 4 at 4 p.m., Susan was in a rush when she stepped into the street at a red light on the northeast corner of 87th Street and Third Avenue. She was holding a pocketbook with long handles in her right hand when someone came up from behind her, plucked the bag from her arm, and rode off on a bicycle.

“He just scooped up my pocketbook,” Susan said. “I was so shocked. I thought someone had just come up behind me and was joking with me.”

Then, she said, “I saw my purse going down the block with this big beefy guy.”

Susan repeatedly screamed, “My purse, my purse.” A police officer in the vicinity aided Susan, calling a squad car to the scene. Susan drove around the neighborhood with police, searching for the thief to no avail. Police found her empty purse at the bottom of a ramp on 95th Street and First Avenue. The suspect had removed Susan’s cash, credit cards, driver’s license, and mobile telephone. In hindsight Susan said of the incident, “I wasn’t paying attention. I had bad luck that day.”

Investigators who noticed an increase in cases of purse-snatching on the Upper East Side said they are considering the grand larcenies – theft of property that, among other factors, exceeds $1,000 or includes a credit card – as a cluster.

In the most recent case, last Friday at 9:20 p.m., as a woman walked out of the subway station at 96th Street and Lexington Avenue, a thief grabbed her purse and fled on a bicycle, officials said. Earlier that day, at 4 p.m., a male snatched a woman’s purse at 60th Street and Lexington and left on foot, officials said.

The day before, at 8:15 p.m., a male rode a bicycle up to a woman on 96th Street and Park Avenue, seized her purse, and fled, police were told.

On August 7 at 4 p.m., a male allegedly took a woman’s bag at 77th Street and Park.

In the first grand larceny of the month, on August 3 at 9:21 a.m., the victim was exiting the subway at 86th Street and Lexington Avenue when a male allegedly swiped her purse.

Investigators noted that in addition to the grand larcenies, there was one purse-snatch robbery – theft by force – on August 5, as well as one purse-snatch robbery attempt, on August 7. In each case, the robber used a bicycle and used his hands as a weapon, officials said.

A neighbor of the woman who was the victim of the attempted robbery last week, Nikki Henkin, said that at some point between 10 and 10:30 a.m. the victim was walking on Park Avenue in the low 70s when a man came from behind and tried to swipe her purse. The woman managed to fend him off, Ms. Henkin said.

Last month there were two other grand larcenies that officials said could be part of the cluster: In each case, a woman’s purse was stolen, and the suspect left by bicycle. One crime occurred on July 21 at 11 a.m, and the other on July 30 at 4:30 a.m.

The use of a bicycle in many of the purse-snatching cases could be indicative of a trend, officials said – or could simply be a popular mode of exit in the warm weather.

Despite the recent flurry of purse snatching cases, however, the number of reported grand larcenies has decreased in the East Side’s 19th Precinct, CompStat numbers show. CompStat is the New York Police Department’s system for tracking major crime. For the 28-day-period through August 14, there were 167 grand larcenies recorded, compared with 192 in the same period last year. For the year there were 1,089 grand larcenies reported in the precinct through Sunday, down 16% from the 1,297 recorded in the first seven months of last year. Citywide, the number of grand larcenies since mid-July was flat, with a total of 3,875 this year, and 3,862 last year, for the 28 days ending August 14, the CompStat report shows. For the year, there have been 59 fewer grand larcenies reported in the city, with 28,197, compared to 28,256 in 2004.