MIAMI -- The husband of a 44-year-old security guard who was shot and killed Sunday at the Dr. Martin Luther King Jr. metrorail station received a garbled hand-held radio message from his wife saying that she had been shot, authorities announced Tuesday at a news conference about the shooting.

Chermaine Joseph-Quetel's husband was on-duty patrolling the parking garage across from the metrorail station on the night she was killed.

"He ran to the scene to find her right behind (where the news conference was being held)," metrorail project manager Denis Shaw said. "He tried to offer her first aid, but she … was beyond his help at that point."

Miami-Dade police said patrons at the station, located at 6300 N.W. 27th Ave., saw Joseph-Quetel patrolling the station by herself at about 10:40 p.m. About two minutes later, patrons heard a gunshot and saw a man run away.

Police said Joseph-Quetel was a five-year veteran of Alanis Security, which contracts with Miami-Dade County to provide security at metrorail stations.

Family members said that Joseph-Quetel was a good person with no known enemies. She was from the Virgin Islands, where she was a police officer for nine years. She leaves behind five children and four grandchildren.

Anyone with information is asked to call Miami-Dade Crime Stoppers at 305-471-TIPS. A reward being offered for information leading to her killer has gone up to $21,000.