In the first week of the new semester, at least five students have been victims of theft on and around Yale’s campus.

At 9.30 p.m. on Jan. 15, Michael Cruciger ’15, who lives in Trumbull College, left his suite door unlocked before crossing the street to go to Ashley’s Ice Cream shop. He said he was there for no more than 20 minutes, adding that leaving his suite door unlocked had not previously caused any problems.

When Cruciger returned, he discovered that his 13-inch MacBook was no longer in his backpack. Cruciger’s decoy wallet, full of expired credit cards, was also stolen. The wallet, he said, was well-hidden in his room and required significant searching to find.

“This was proof that the perpetrator had extensively been through my belongings,” Cruciger said.

Cruciger immediately reported the theft to the Yale police.

A daily crime log on the YPD’s website recorded that a theft had been reported at 241 Elm St., the address of Trumbull College, on Jan 15. That case is closed, the report said. However, additional crime logs from the rest of the week showed four more thefts in Trumbull College reported on Jan. 15 and Jan. 17. Each of these cases remain open.

University Spokesperson Tom Conroy said in a Tuesday email to the News that Yale detectives are investigating the thefts and are actively pursuing several leads. The YPD could not be reached for further comment Tuesday.

Several students reported suspicious activity to Trumbull College Master Margaret Clark on the night Cruciger’s laptop was stolen, Clark said.

Axell Meza ’16 was with two friends in his common room when a person he did not know entered his suite without knocking.

The individual, described as a college-aged, African-American male, looked shocked when he saw Meza and his friends in the common room and claimed to be looking for a man named Josh, Meza said. When Meza asked him for more details about Josh, the man said Josh was a freshman with whom he attended Yale, Meza said.

Meza tried not to seem alarmed while the individual was in his common room due to a fear that he could be armed. Nevertheless, the individual appeared calm and unthreatening, and thus, Meza said, he felt no need to call security immediately.

Shortly after the encounter, Meza heard his entryway door shut abruptly, and he took that to mean the suspicious person had gone.

According to Cruciger and Meza, other students in entryway J encountered the same individual that evening, claiming to be looking for Josh.

“Other students reported that in that area, and at that time, they saw someone that was walking through and standing near opening doors,” Clark said, adding that the students who saw the individual had said they did not feel threatened, even though they could tell that he was not a Yale student.

On Monday evening, there was another sighting in Trumbull of individuals whom students identified as suspicious. The YPD was immediately called and searched the premises, asking students if they had seen anything unusual.

Nora Etienne ’17 told the News she was studying in the Trumbull library when two police officers came in and asked whether anyone in the room had recently entered. She told them that no one had. Etienne added that the officers, guided by a Yale student, continued searching through Trumbull for a few minutes before leaving the college.

Clark said she was not aware of the presence of police until she was alerted by a student. She was then told by the YPD that nothing untoward had been discovered.

“The people who were sighted could be perfectly innocent, but nothing is known at this point,” Clark said Monday night.

Earlier that night, the year’s first campus-wide alert from YPD Chief Ronnell Higgins reported another incident involving three undergraduates. The email said that two men on bicycles approached the students from behind, demanding that they turn over their backpacks.

A Jan. 20 press release from New Haven Police Department Spokesperson David Hartman said the undergraduates had told investigators that one of the two men had a silver-colored handgun with which he threatened the undergraduates. According to Hartman, the undergraduates handed over their backpacks, which contained rock-climbing equipment, as well as an iPhone in a black case.

In addition to this robbery involving three Yale students, the NHPD reported three other incidents of robbery on Jan. 19. The report did not include the Trumbull thefts.

In emails sent out to Trumbull students over the weekend, Clark reminded students to stay vigilant and careful, adding that hangers should not used to keep doors unlocked.

Cruciger said he currently has no further information on his case, but he encouraged anyone with knowledge to step forward.

“All I want is for something to be done,” he said. “My laptop contains all of my photos and files from three-and-a-half years at Yale.”

Students with information on the cases can contact the YPD at 203-432-4400.