Police release 1 of 4 suspects detained over blast, beheading in France seen as terrorism

Police officers guard the road leading to a plant in Saint-Quentin-Fallavier, southeast of Lyon, France, Saturday, June 27, 2015, where an attack took place yesterday June 26. A spokeswoman for the Paris prosecutor's office says one of the four suspects detained over an explosion and beheading in southeast France has been released, while the suspected assassin isn't speaking to investigators. (AP Photo/Michel Euler) (The Associated Press)

Police officers guard a road leading to a plant which was attacked on Friday in Saint-Quentin-Fallavier, southeast of Lyon, France, Saturday, June 27, 2015. A spokeswoman for the Paris prosecutor's office says one of the four suspects detained over an explosion and beheading in southeast France has been released, while the suspected assassin isn't speaking to investigators. (AP Photo/Michel Euler) (The Associated Press)

Police officers guard a road leading to a plant which was attacked on Friday in Saint-Quentin-Fallavier, southeast of Lyon, France, Saturday, June 27, 2015. A spokeswoman for the Paris prosecutor's office says one of the four suspects detained over an explosion and beheading in southeast France has been released, while the suspected assassin isn't speaking to investigators. (AP Photo/Michel Euler) (The Associated Press)

A spokeswoman for the Paris prosecutor's office says one of the four suspects detained over an explosion and beheading in southeast France has been released, while the suspected assassin isn't speaking to investigators.

Yassine Salhi, a truck driver with a history of radical Islamic ties, remains in custody Saturday in Lyon a day after allegedly crashing a truck into an American-owned chemical warehouse and hanging his employer's severed head on a factory gate.

Paris prosecutor's office spokeswoman Agnes Thibault-Lecuivre said investigators have not turned up any motive or possible foreign connection. Under French anti-terrorism laws, he can be held up to four days before either being released or handed preliminary charges and locked up.

Salhi's wife and sister remain in custody, while another man was released without charge.