BOZEMAN, Mont. -

State investigators are joining the search for a Butte woman and her newborn son.

A warrant is still out for 29-year-old Michelle Yallup. Police accused her of being high on meth when she delivered a baby in the Anaconda Hospital last month.

Hours later, she walked out with her newborn, and officials say that baby boy could be in danger.

At the time, we asked why the state didn't pull out all the stops to find her. We were told Yallup has custody of the baby, so they could not issue a state-wide Amber Alert. Instead, they posted a limited advisory to neighboring counties, which ran out 48 hours after Yallup took off.  

To date, she and the newborn are still missing.

NBC Montana asked Deer Lodge County police why it took more than two weeks for them to include the state in their search.

Law enforcement officials are looking for Yallup in multiple jurisdictions, and after following up on more than 30 leads without any luck, Deer Lodge County officers decided it was time to get state investigators involved to help find Yallup and her child.

Yallup and her newborn baby disappeared on June 18. Since then, Anaconda-Deer Lodge police have followed leads taking them to Great Falls, Butte, campgrounds in Powell County, and even as far as Billings. But Yallup and her son are still missing.

"We haven't received any information lately," explained Butte-Silver Bow Sheriff Ed Lester. "We did investigate a number of tips last week, but those tips proved to be false."

This week, Anaconda-Deer Lodge County officials asked state investigators to join in the search.

"The way it works here in Montana is our Division of Criminal Investigation, one of its primary purposes is to support local law enforcement agencies on complex criminal investigations," explained Montana Department of Justice Communications Director John Barnes.

Barnes said until the state is requested, they cannot step into investigations of this nature.

"We can only get involved when asked by a county sheriff, county attorney or city police chief," Barnes said.

Lester said additional investigators will hopefully speed up the search.

"There's somebody out there who knows where the baby is and where the mother is, and hopefully they'll see media coverage or call our department and we'll be able to respond quickly, especially with the added resources from the state," Lester said.

Barnes agreed, explaining the state investigators will provide more manpower to keep the case from going cold.

"We're going to put all the resources we can into this and try to figure out what happened," he said.

Last month, we told you how social workers and investigators were concerned about a loophole in Montana that prevented an Amber Alert from being issued in this case. This case did not meet the requirements for an Amber Alert, because the child did not have a legal name, and technically was still in custody of the mother. Authorities say this case might be used to change the requirements.

Yallup is 5-foot-6, brunette, and weighs about 120 pounds. Her baby boy has dark hair and eyes and, at the time of the disappearance, weighed 6 pounds, 15 ounces.

Anyone with information is urged to call Anaconda Police at (406) 563-5241.