Four people have been arrested in connection with the murder of a man found in Penny Road Forest Preserve last year. 

David P. Campbell, 27, of Waukegan, was found naked and partially submerged in Penny Road Pond on July 7, 2011. Investigators say he was strangled and ruled his death a homicide. 

Nearly a year later, arrests have finally been made in the case. 

Nadia Palacios, 22, of the 3500 block of Winhaven Drive, Waukegan was charged with two counts of first-degree murder. Roberto Guzman, 24, of the 1000 block of Berwick Boulevard, Waukegan; Eric Castillo, 24, of the 38400 block of North Sheridan Road, Beach Park; and Jose Horta, 19, of the 300 block of Edison Court, Waukegan were also charged. 

Police say the murder was in retaliation of a crime Campbell allegedly committed against the suspects. 

Palacios was arrested after reports of shots fired were reported in Waukegan on Sunday. While she was interviewed by police, they learned of her involvement in the Campbell murder. She was charged with the crime and bond was set at $2 million. The other three suspects were arrested Wednesday, and bond was set at $3 million. 

"First and foremost, Cook County Detectives did an outstanding job in investigating this homicide. Our detectives were able to supply the last piece of the puzzle; and together, our departments were able to solve this murder.  My heart goes out to the family of Mr. Campbell.  I hope this brings some closure to their grief," Waukegan Police Chief Daniel Greathouse said.