PARIS (AP) — A French prosecutor opened a formal kidnapping investigation Saturday in the disappearance of a 9-year-old girl who went missing from a wedding celebration last weekend.

Grenoble deputy prosecutor Laurent Becuywe said at a news conference that no leads would be cast aside in the investigation, including the possibility that the girl was a victim of an accident.

Two men, both 34, were released without charges Friday night after being questioned, Becuywe said. They were detained Thursday and Friday.

Investigators sought explanation from the men on "some elements," he said. "As things stand, it was decided these elements were not enough to justify charges".

He declined to elaborate.

Hundreds of volunteers were helping search Saturday for the girl, who has been identified only by the first name Maelys.

She last was seen at around 3 p.m. on Aug. 27 at the village hall in Pont-de-Beauvoisin, 85 kilometers (53 miles) from Lyon in southeastern France.

Police dogs found the girl's scent but lost it in the hall's parking lot, suggesting she may have been forced into a vehicle or gotten into one voluntarily.

Police requisitioned photos and videos taken by wedding guests to look for any unusual activity.

Becuywe said police have questioned more than 200 potential witnesses and carried out about 40 house searches in recent days.

"The absolute priority is to find the young Maelys", he added.

Until Saturday, the girl's disappearance was subject to a preliminary investigation. The formal investigation has two judges assigned to the case.