Investigators have issued an arrest warrant for a gang member in connection with the slaying of a 69-year-old Denver man, whose body was found near Lookout Mountain.Investigators are trying to locate Edwin Ernesto Rivera Gracias, 27, who is wanted on investigation of first-degree murder in the killing of Richard Limon, said Jefferson County sheriff's spokesman Mark Techmeyer.On Tuesday night, investigators arrested three other people -- Raul Nunez-Soto, 47, and Tina Moya, 38, and a 17-year-old girl -- in connection with the Limon killing.Rivera Gracias, who is known to have a handgun, claims to be a member of the Mara Salvatrucha -- or MS-13 -- gang, Techmeyer said. He also claims to be from El Salvador and may carry identification from that country.He is described as 5 feet 10 inches tall and 170 pounds with short brown hair.Rivera Gracias has several tattoos, including "LA" on his right forearm, Maria on the left side of his left chest, Nena on his left hand, El Salvador down the back of his right arm, 503 down the back of his left arm and MS 13 across his back.Rivera Gracias has most recently lived in Denver and is known to frequent the area of South Federal Boulevard and West Yale Avenue. In the last two years, he has also resided in California and Louisiana.Limon's body was discovered off the side of Lariat Loop Road on Mount Zion on Aug. 17. The gruesome discovery was made by two bicyclists who stopped to rest by the side of the road that goes from Golden to the top of Lookout Mountain.Investigators said they developed information that led to the arrest of Nunez-Soto, Moya and the 17-year-old girl, whose name was not released because she's a juvenile.Nunez-Soto and Moya were held without bond on investigation of first-degree murder. The teen was held without bond at the Mount View Youth Services Center on investigation of first-degree murder.Video from Airtracker7 on the day Limon's body was found showed the corpse was about 30 feet off the side of the road. From the video, it appeared Limon's head had been wrapped in cloth or tape and his hands may have been bound.Investigators asked anyone with specific knowledge about Limon, or anyone who may have been in the area of Lookout Mountain on Aug. 16 or 17, or who has information related to the investigation, to call the Jefferson County Sheriffs Office tipline at 303-271-5612.