French officials say a second man has been detained in an investigation into an alleged plot to attack a church near Paris.

The detention occurred Sunday in Saint-Ouen north of Paris, according to a French security official. The man's DNA was found on a hairbrush in the house of Sid Ahmed Ghlam, the chief suspect in the thwarted attack, the official said. The official wasn't authorized to be publicly named.

The Paris prosecutor's office confirmed that a suspect is in custody.

Authorities say Ghlam, a computer science student, planned an attack on a church in Villejuif south of Paris, and is suspected in the killing of a woman nearby. He was arrested and handed preliminary terrorism-related charges.

It is unclear whether the man detained Sunday was involved in the plot.