Four men walking alone on North Campus were reportedly robbed at gun- and knifepoint Monday night, bringing the total number of armed robberies occurring near campus this semester from zero to five in less than two days.

The Department of Public Safety believes the latest incidents all occurred within a 45-minute time span, between 8 and 8:45 p.m. Monday.

All the victims were walking near Cram Circle between Bishop Avenue and Hubbard Street on North Campus, near the Northwood Housing I and II complexes.

DPS Lt. Benny Chenevert said the victims each reported that they were approached by two young men - one who had a large semiautomatic handgun and the other who held a knife.

The first suspect is described as a white male between 15 and 18 years old, standing between 5-foot-7 and 5-foot-8 and weighing approximately 200 to 230 pounds. He was wearing a dark blue jacket and his face was covered with either a hood or a hat, according to the crime alert issued by DPS yesterday.

The second suspect was described as a black male between 13 and 16 years old, standing about 5-foot-6 and weighing 130 pounds. According to the crime alert, he has a light complexion, short black hair and was wearing a dark blue or black hooded jacket.

It is unknown which suspect was carrying which weapon.

The victims told police the suspects were originally polite, asking for directions before robbing them.

Nobody was injured and Chenevert said he did not know how much money had been taken or if any other possessions were stolen.

Since the incidents, DPS has taken several measures to ensure the safety of students, including increased patrols in the area, Chenevert said.

"We are obviously taking it very seriously," he added. "We have dedicated several officers to this case, including police, detectives and canines."

DPS spokeswoman Diane Brown said patrols were increased Monday night following the incidents and will continue to be increased for an undetermined amount of time.

The incidents occurred only one day after the semester's first armed robbery, in which a male student walking down a path in a wooded area on North Campus was robbed by two men around 11:30 p.m. Sunday. That robbery occurred near the south side of Bursley Residence Hall.

The two suspects in that robbery were described as being black males wearing dark clothing. One suspect stood 5-foot-8 and the other 6 feet, according to the DPS crime alert issued for the incident. Both were college-aged.

"This is very unusual, to have five armed robberies in 24 hours," DPS spokeswoman Diane Brown said, adding that DPS is also offering a reward of up to $1000 for information that leads to the arrests and convictions of the suspects involved in Monday's incidents.

She could not say the last time DPS offered a reward for information, but one was offered over the summer after multiple LCD projectors were stolen from campus buildings. After offering the award, multiple people were apprehended, Brown said.

Persons with information are asked to call DPS at 763-1131 or the University's anonymous tip line at 1-800-863-1355.

Chenevert could not say for sure whether yesterday's armed robberies are related to the one occurring Sunday.

"It may be connected to the similar incident on Sunday night," he added.

Before this week, the last armed robbery to occur on campus and warrant a crime alert took place July 28 in the Church Street Parking Structure, in which two suspects used a small caliber handgun to rob two victims. One of those suspects, 23-year-old Ypsilanti resident Keith Mitchell-Lucas, was arrested in September and arraigned on four felonious charges.

Another incident in the Church Street Parking Structure that occurred Sept. 13 involved an 18 to 23-year-old black male standing 6-foot-3 to 6-foot-5 who claimed to have a gun. Nothing was taken in the incident and the victim told police he did not see a weapon.

Chenevert said in order to ensure their personal safety, students - regardless of gender - should not walk alone, especially at night and in isolated areas.