A 16-year-old Afghan was arrested in connection to the fatal shooting of nine people in Munich on Friday by German-Iranian gunman Ali David Sonboly, under suspicion that he knew about the shooting beforehand and may have even sent the Facebook message that lured victims to their death.

Munich Police have confirmed that a 16-year-old Afghan who was friends with the gunman has been arrested on suspicion of acting as an accomplice in the fatal shooting in the Bavarian city, and for failing to report the gunman’s plans, Deutshe Welle reports.

Police are also investigating whether the teen sent the Facebook message which lured the victims to the McDonald’s restaurant where the 18-year-old German-Iranian dual citizen Ali David Sonboly opened fire.

A statement issued by Munich Police confirmed that the teen, who has not been named, reported voluntarily to the police station on Friday following the shooting and was questioned on his relationship with the shooter.

On the Saturday, police investigations found contradictions in the youth’s statement, which lead to suspicions that the Afghan was a possible accomplice in Friday’s shooting. A warrant for the Afghan’s arrest was issued and he was arrested on Sunday 24 July.

Police confirmed that the youth had been communicating with Sonboly via WhatsApp, but deleted his chat history after the fact. However, the restored chat history shows that the 16-year-old had knowledge regarding the weapon which may have been purchased illegally on the dark web.

Police also revealed that the Afghan met the 18-year-old killer before the shooting at 4pm in the vicinity of the crime scene.

“For these reasons,” the statement read, “it can be assumed that the 16-year-old was not directly involved in the act but possibly knew about the planned killing spree. The Munich criminal court therefore requires the arrest of the youth on suspicion of failure to report a planned offence”.

Munich police are also currently investigating whether the arrested teen is responsible for the Facebook message which lured the victims to the shopping complex.

The Afghan suspect’s involvement and arrest may dispel assertions that Sonboly was a lone wolf acting on his own.

Sonboly shot and killed nine people and wounded 35 on the evening of Friday 22 July when he opened fire at a McDonald’s outside of a shopping mall with an illegally-purchased Glock 17. He then turned the weapon on himself.

This was the second of four attacks to rock Germany in the space of one week. On Monday 18 July, an Afghan migrant attacked passengers with an axe on a train in Wurzberg. On the morning of Sunday 24 July a Syrian migrant went on a machete-wielding rampage hacking one pregnant woman to death before being mowed down by a BMW and arrested, followed that night by a Syrian migrant who detonated a suicide pack, killing only himself but injuring 12 others, outside of a music festival in Ansbach.