Police arrested three suspects this week in the murder of a Lincoln teen-ager who was found dead in Van Dorn Plaza Shopping Center on Feb. 18.The murder was the result of a botched robbery in the parking lot, Lincoln Police Chief Tom Casady said.Brandon Pickinpaugh was shot once in the head while the three men tried to steal the approximately three quarters of a pound of marijuana and the $950.40 Pickinpaugh had with him, police said.Casady said Pickinpaugh had been dealing drugs.All three men were arrested for other crimes, and the County Attorney will charge them for the homicide after reviewing the files.Pickinpaugh, 17, was found shot lying on the ground next to the green Chevrolet Cavalier he was driving.A McDonald's customer who was parked near Pickinpaugh saw his body when he was returning to his car around 9:30 p.m. and called police.Pickinpaugh, a Hastings native, had been living in a group home run by Robert and Marilyn Beggs since he became a ward of the state in December 1997. He was also a junior at Lincoln Southeast High School.None of the suspects arrested were group home residents, but several of them were known gang members, Casady said.Jeremy Kurtzer, 18, was arrested Monday evening at 6011 S. 43rd St. for possession of stolen property. Police said Kurtzer gave a stolen handgun to another teen-ager who robbed an ATM in January.Derek Graves, 20, was arrested for several outstanding warrants Monday afternoon when police served a search warrant at his apartment, 4600 Briarpark Dr., Apt. 112.Graves was wanted for burglary, possession of a controlled substance and refusal to comply with a police officer.The SWAT team found several guns in Graves' apartment, and they arrested Graves' roommate, Tanner Andrews, 19, for having a .38-caliber revolver that was stolen in a November burglary. Andrews has not been linked to the murder.Monday evening, police arrested Jedidiah Ngirchoimei, 19, for the attempted robbery of Brandon Pickinpaugh.Ngirchoimei, Graves and Kurtzer are all implicated in the murder, but police have not said which one shot Pickinpaugh.During their investigation, Casady said police encountered several teen-agers who concealed evidence or lied to them.Dennis Sciscoe, 19, was arrested Tuesday morning for concealing evidence. He was charged with accessory to felony.Casady said that more arrests could follow for accessory to a felony and giving false information to a police officer.In recent homicide investigations, Casady said the trend has been not to tell the truth to police.But Casady said investigators feel strongly that people need to be arrested for lying."This isn't the Paula Jones lawsuit," Casady said. "If you lie in a murder investigation, you get arrested."While police had Graves' apartment under surveillance, Casady said veteran investigators were taken aback by the number of teen-agers who hung out at the apartment even though they were aware of the gang activity."It deeply concerns me to see 15-, 16- and 17-year-old kids hanging out here after school," Casady said.Casady said that this murder should be a warning for parents."The message to parents is wake up and pay attention to who your kids are hanging around with," Casady said.Parents need to get their children away from people involved in these activities, Casady said, so they are not subject to the risks.It is dangerous to normalize this kind of conduct, Casady said."When you get a couple of wanna-be gangsters together with a gun, you get a wanna-be homicide."