In response to a recent wave of robberies and attempted robberies in the Elm City, the Yale and New Haven police departments have increased joint patrols in and around campus this week and used undercover tactics in an effort to prevent several crimes from occurring.

Both police forces have made several preemptive arrests in response to suspicious activity over the past few days, which may have resulted in the prevention of several robberies around campus. The YPD has also enlisted undercover police officers and new walking patrols to track down suspects who use bicycles to flee from crime scenes, YPD Chief James Perrotti said.

“If you’re a student of risk management like I am, what is predictable is preventable,” Perrotti said. “We are trying to get our officers out there early in the evening to watch for any kind of suspicious activity so we can get these guys before robberies actually happen.”

Undercover officers from the NHPD arrested a man on a bicycle for an attempted purse snatching near the intersection of Howe and Chapel streets late Wednesday night, and some went on joint patrols with the YPD, Perrotti said.

“Luckily, there were New Haven police officers undercover as this was all occurring, and they were able to prevent the robbery,” he said.

The NHPD was unable to be reached for comment, but Yale Deputy Secretary Martha Highsmith said she thinks the YPD is working well with the NHPD.

Although no other robbery attempts were reported, Perrotti said several other arrests were made late last night in the areas immediately surrounding campus.

One arrest took place near the intersection of Elm and Howe Streets. Perrotti said a joint patrol of Yale and New Haven police officers noticed a youth on a bicycle who was engaging in suspicious activity.

“As they neared the individual, the noticed the butt of a gun in the waistband to his pants,” he said. “They found a large, black BB gun that looked real.”

The 16-year-old male was charged with carrying a weapon, disorderly conduct and interfering with the police.

More arrests took place on Chapel Street near Book Trader Cafe. Perrotti said a joint NHPD and YPD patrol followed some individuals in their early twenties who were engaging in suspicious activity. When the police approached the individuals, they left their car and ran to different areas of the campus.

When police eventually caught up with the suspects, they were found carrying BB guns identical to the gun of the suspect of the robbery earlier in the night. But Perrotti said the crimes do not appear to be related.

Perrotti said robberies committed on bicycles have become increasingly common in the New Haven area.

“They are easy to maneuver when in large crowds of people,” he said. “The suspects can always get off the bikes and start walking, which makes it harder for the police to locate them.”

Although Highsmith said a long-term solution is required for the recent increase in crime, she said Yale is currently being confronted with a “situational issue.” In order to effectively deal with this in the short-term, she said police must work together and students must be increasingly vigilant.

“These crimes are not so much about the people themselves,” she said. “They are crimes of opportunity.”

Perrotti said it is important for students to pay attention to their surroundings at all times.

The robbery of a Yale research assistant Tuesday night near the intersection of Dwight and George streets occurred partly because the victim was walking alone, he said.

“There was a lone person who was on Dwight walking after dark, and there was a group of teenagers, two of whom were on BMX bikes,” Perrotti said. “While he [the victim] was crossing the street, one bike blocked his path and the others began to assault him.”

Although the suspects demanded money, Perrotti said they fled as soon as the student began to yell for help. The NHPD responded to the call for help, but was not able to make an arrest.

Many students said they rely on their sense of intuition when deciding whether to walk alone at night.

“If I walk outside after I’ve been doing something and I get that feeling that something wrong is going to happen then I would call 2-Walk or minibus,” Erin Cawley ’08 said. “I would be more prone to now, because of all the things that have happened.”

Christian Barjum ’08 also said he will now be more vigilant.

“So far, I have never felt like I have been in danger, but I would probably be more likely now.”

Perrotti said students should follow such instincts in situations that make them feel uncomfortable.