PARIS — The man who decapitated his employer and hung the severed head wrapped in Islamic flags took two photos of the macabre scene and sent them almost immediately to a friend in Syria, a French prosecutor said Tuesday.

The attack bore the trademark of the Islamic State group's propaganda, and the friend has already requested permission from the extremists to distribute the snapshots, said Paris prosecutor Francois Molins.

Yassin Salhi, a truck driver with a history of radical Islamic ties dating back to 2003, was seized by firefighters at the Air Products chemicals warehouse. According to Molins, Salhi has denied he was motivated by terrorism and said he neither remembers the beheading nor sending photos.

"According to him his motive was only personal and not terrorist. One does not exclude the other," Molins said. "He decapitated his victim, he hung the head on a chain, and he wanted to get the maximum publicity possible."

Molins has requested preliminary terrorism charges to be filed against Salhi and has opened a formal terrorism investigation, including into his ties with the man in Syria, identified as Sebastien Younes.

Molins said investigators recovered a message in which Younes appeared to be claiming responsibility for inspiring his friend.

Air Products officials have said Salhi had an entry badge for the site in Saint-Quentin-Fallavier, near Lyon, and had never caused problems in the past.

Molins said Youens, who has been in Syria since November, was in contact with Islamic State higher-ups about the photos. The Friday attack came days after Islamic State militants urged followers to strike during the Muslim holy month of Ramadan.