BOSTON -- Police in New York City have released a sketch of a man they want to talk to in connection with the death of a Boston graduate student. Imette St. Guillen was found dead in a vacant Brooklyn lot last weekend.

NewsCenter 5's Amalia Barreda reported that on the day St. Guillen would have turned 25 years old, New York police are on the hunt for a possible suspect described as possibly Middle Eastern, in his 30s, with a dark complexion.

According to The New York Post, the man is the same man who police said was posing as a cab driver on Feb. 12 when he allegedly picked up a 32-year-old woman headed for the airport. Police said he sexually assaulted her and tossed her out of the cab near the vacant lot in Brooklyn where St. Guillen's body was found.

As police work the investigation, the young woman's mother talked about the daughter she lost.

"She had a tremendous amount of respect for people, and I think people had respect for her because of the way she treated them," Maureen St. Guillen said.

St. Guillen's family released a statement Thursday that read, "As you know, today would have been Imette's 25th birthday. While we are dealing with the difficulty of finalizing arrangements for her services, we do not want that to overshadow the meaning of the day. We plan on celebrating Imette's life with family and friends by sharing stories about her life."

One of the last people to see her alive was her best friend, Claire Higgins. They left the Pioneer Bar in the Bowery at about 3 a.m. Saturday. The women parted ways because St. Guillen did not want to go home.

In a statement reported in the Boston Globe, Higgins said, "Clearly this is a very difficult time for me. I am heartbroken and miss her deeply. I was extremely blessed to have experienced a friendship like the one we shared."

The family, who has also been pleading for the public's help in catching the killer, is reportedly putting together a $30,000 reward for information that will lead to the capture of St. Guillen's killer.