BERLIN (AP) — German police have arrested two teenagers suspected of killing an acquaintance and his parents in Bavaria two weeks ago, authorities said Friday.

Initially, authorities believed that the 21-year-old victim had shot his 64- and 60-year-old parents and then committed suicide at their home in the affluent lakeside town of Starnberg, south of Munich. Two firearms were found lying next to him.

Further investigations indicated that a 19-year-old friend of the young man might have a substantial cache of illegal weapons. After he was arrested, the teenager allegedly told police that he had shot dead the family.

Andrea Mayer, a spokeswoman for Munich prosecutors, said the suspect took a video of the crime scene that forensic investigators were able to restore from his mobile phone.

An 18-year-old man was also arrested on suspicion of having driven the older teen to and from the site of the shooting, which investigators believe took place in the early hours of Jan. 11.

Both are being held on suspicion of murder and accessory to murder, respectively.