For the fourth time in about two weeks, an armed robbery has been reported in Brookline on or near the Boston University campus, authorities said.
In the latest one, police are investigating an armed robbery of a woman at 808 Commonwealth Ave., which occurred Tuesday night on the BU campus, Boston police said. One of the suspects may have fired a gunshot, David Estrada, a Boston police spokesman, said Tuesday night.
No other details were immediately available.
Another armed robbery was reported Friday when a 22-year-old recent BU graduate said that three teenage black males, one brandishing a gun, robbed him near the intersection of St. Paul and Thatcher streets around 5 p.m., according to a report by Brookline police.
The trio later ran toward Commonwealth Avenue. An iPhone, car and house keys, and a wallet containing $22 in cash, a license, and credit and debit cards were stolen, the report said.
The robberies, in a residential area where such crimes are rare, have stirred unease around campus and in the surrounding community and have prompted warnings from BU and Brookline police.
In three of the cases, current BU students or recent graduates have been the victims, according to the BU Today website.
It was not known Tuesday night if the latest victim was affiliated with BU.
The suspects in the three cases prior to Tuesday’s incident have been described as black males who appeared to be between 16 and 24 years old. They were wearing sweatshirts, police said.
No injuries have been reported in the robberies, and no arrests have been announced.
BU and Brookline police stepped up patrols after the incidents. The two departments also issued alerts for the campus and surrounding communities.
Officers have not said whether they believe the robberies are connected.
In another one of the robberies, Brookline officers responded to Egmont and St. Paul streets shortly after 5 p.m. Sept. 25, when three males reported being robbed at gunpoint while walking home from Commonwealth Avenue.
Three other males followed the students before one walked in front of them, pulled out and cocked a black semiautomatic handgun, and placed the gun against the stomach of one of the students, a Brookline police report said.
Cash, cellphones, and a laptop were taken in the robbery, police said.
Two days earlier, on Sept. 23 at about 3 a.m., a male and female said they were robbed at gunpoint near an alley that runs between Thorndike and Fuller streets near Hamilton Road as they walked home from Brighton, Brookline police said.
Globe correspondent Derek J. Anderson contributed to this report. Matt Rocheleau can
be reached at mjrochele@