MIAMI -

Police on Thursday arrested a second man accused of killing a security guard.

Police charged 27-year-old Gregory Lewis with first-degree murder and armed robbery.

Police say, on August 17, Lewis and Quintin Vicks and some others ambushed Robert Nelson, who was inside his car patrolling an apartment complex at 27085 SW 138th Court, shooting him several times. They killed him and stole his gun.

Nelson worked for North Miami-based 50 State Security.

"It's devastating and it's not something that you can ever prepare for," said 50 State Security President John Williams. "He's a great, great guy, very cordial, very friendly. The feedback from a lot of people [is] that he was somebody who made them laugh all the time, he was always making jokes and having fun."