Gwinnett County police announced Friday the arrest of a suspect in the four-month-old investigation of the killing of a man outside his Norcross apartment.

Justo Luis Alonzo is being held without bond in the Gwinnett County Detention Center on charges including murder, possession of a firearm during the commission of a crime and criminal attempt to commit armed robbery in the death of Timothy Kemp, authorities said.

“Leads in this case were exhausted quickly immediately following the crime. Additional information recently came to light which led to the arrest of Alonzo,” police said in a prepared statement.

Police did not say what led them to the 29-year-old Alonzo except to say, “Aspects of this investigation are still ongoing.”

Other charges against Alonzo include theft by taking, criminal trespass and violation of probation, according to the Gwinnett County Sheriff’s Office.

Kemp, 46, was found dead with one gunshot wound in the chest less than 10 feet from his home in the Harbin Springs Apartments on Twin Springs Trail the morning of July 25.

Kemp's son, Dionte Johnson, 21, told The Atlanta Journal-Constitution shortly after the killing that his father worked as a janitor at Hartsfield-Jackson International Airport and contracted with Coca Cola doing maintenance.