Tucson Police report no major breakthroughs in the case of missing 6-year old Isabel Celis.

At a press briefing on Sunday afternoon, Lt. Fabian Pacheco said, police have received 350 or more leads in the case.

Pacheco says detectives have had the weekend to sit down, and review lead sheets, and other tips in the case.

"This weekend they've had a chance to really sink their teeth into this, and get a lot of things done."

Pacheco says they have also followed up on a "handful of tips" that have come in from Nogales, Sonora.

Police say detectives continue to receive a lot of information, but the pace is a lot slower.

"The weekend has given them an opportunity to catch their breath, and plan their strategy for next week."

Detectives have spoken with one person who was seen in a surveillance video last Friday. Pacheco believes at least two other people have come forward. Police have not identified a sixth person who was seen in the video has not come forward.

Pacheco says Isabel's parents are still cooperating with investigators.

"By all means, we would really love to have Isabel back at her parents, and have this case resolved, and we are doing everything possible to that end."

According to Pacheco, about 10-13 F.B.I. agents are working on the case. About 8-10 Deputy U.S. Marshals are also assisting in the investigation.

Police urge anyone with information to call 9-1-1 or 8-8 Crime.