TUCSON, Ariz. -- A missing child can sometimes pull parents apart.
Not Becky and Sergio Celis, their bond has only grown stronger.
"Because we've become stronger and we are becoming stronger, we will be ready for when Isa comes home because whatever she has to deal with we'll being dealing with her," Becky said.
Their daughter, Isabel, 6, was abducted 6 months ago in April.
But the heartache didn't stop there.
Child Protective Services stepped in, making sure their two boys were safe.
And that's when Sergio stepped out, leaving the house for awhile.
"Everything was voluntary. I was saying, 'Do whatever you need to do,'" Sergio said. "Yes, it was heart wrenching, on top of the fact of everything that already happened, to be separated, but we were more than willing to do everything we absolutely could."
Both parents said this was the first contact they had with CPS despite reports saying otherwise.
The Celises are now using their home in Tucson as a billboard. Missing person posters are plastered around the home, asking for the community to keep praying
Becky said the family misses Isabel so much.
"The boys were like, 'Let's watch TV in your room, Mom,' and so I have Julian and Sergio lying next to me," Becky said. "Usually, it would be all three of them and all the sudden I would be at the foot of the bed. I really missed her then."
So much so, the family is now working with a private investigator in California.
The PI has a background in law enforcement and was recommended to Sergio's sister.
"I can't say that they're following up on different leads, but maybe different angles that the police were not investigating," Sergio said.
The family has spoken to the PI once or twice they said via conference calls.
"I feel like she's somewhere north or in California somewhere out there," Becky said.
The parents believe Isabel is in California because of a strong tip that came in. They don’t believe she is in Arizona.
Sergio said any new information is given directly to the Tucson Police Department, who he said he is frustrated with.
"The fact that communication has been what is has been for two to three months, which is non-existent," Sergio said.
The upset father also accused detectives of not following up on a lead for several weeks.
"That is, that is I want to say unacceptable. How could that be?" questioned Sergio.
Via email a spokesperson addressed that question to 3TV:
"With respect to the information you received from the Celis family, I am not sure what tip they are specifically referring to. However, I can assure you that each and every tip received is thoroughly investigated. In addition, some tips cause investigators to go back and conduct additional review of previous tips that were received. The detectives and analysts that continue the investigative efforts are meticulous in their examination of every tip received. Nothing is ever "ignored." Detectives are always available to the Celis family. I am not sure who they were specifically trying to get in touch with or when," said Sgt. Maria Hawke.
Sgt. Chris Widmer said during an on-camera interview that two detectives are still working on this case, and at times they are used for other cases, too.
3TV asked to speak with the chief of police for an update and we're told he wasn’t available because there aren't any new updates.
More than 2,000 leads have come in, but Widmer said the incoming tips are slowing down.
Widmer could not answer questions specific to details of the investigation.
"We release what we can to the public without interfering with the investigation," Widmer said. "There may be details that we're holding, but there's a purpose for it."
We're told sex offenders in Isabel's neighborhood have been interviewed once, twice up to four times if needed
No one has been ruled out as suspects, not even Isabel’s relatives or parents.
The Celises said they aren't planning on moving or changing their phone number, hoping to hear Isabel's voice soon