Motions in the triple-murder case show the defense might pursue Chris Watts' claim that his wife, Shan'ann, strangled their two daughters

The defense for accused triple-murderer Chris Watts might base their strategy on the suspect’s claim that his slain wife — and not Watts himself — killed their two young daughters, a legal expert tells PEOPLE.

“The jury’s going to make a determination whether to believe him or not,” says Ambrosio Rodriguez, a former prosecutor who is now a criminal defense lawyer and is not connected to the case. “If a jury believes him, he’s going to walk.”

Prosecutors in the Colorado homicides say they have evidence that Chris, 33, was having an affair with a co-worker at the time they allege he killed his 15-weeks-pregnant wife, Shan’ann, 34, and their two daughters, 4-year-old Bella and 3-year-old Celeste, earlier this month.

Shan’ann Watts (center) and her daughters
| Credit: Shanann Watts /Facebook

He has not yet entered a plea to multiple charges against him, including first-degree murder and tampering with a body in all three deaths. His attorney has not responded to PEOPLE’s requests for comment.

Chris allegedly acknowledged to investigators that he strangled Shan’ann, according to an arrest affidavit. The incident allegedly occurred in the early hours of Aug. 13, when Shan’ann had returned home from a business trip. (Chris denied the affair to investigators, the affidavit states.)

From left: Shan’ann Watts and husband Chris
| Credit: Shanann Watts /Facebook

Chris claimed to investigators he told Shan’ann he wanted a marital separation. Then, he claimed, he briefly left Shan’ann alone, then returned to speak with her again and saw Shan’ann via a baby monitor “actively strangling” Celeste while Bella lay “sprawled out on her bed and blue,” according to the affidavit.

Chris claimed he then “went into a rage” and killed his wife — an alleged scenario that appears to be driving his early defense strategy after Chris was charged Monday with all three of the murders, says Rodriguez, a Los Angeles-based attorney and former senior deputy district attorney.

According to Rodriguez, Watts’ defense strategy is revealed by a defense motion filed Aug. 17, one day after the three bodies were found on property owned by Chris’ former employer. The motion — already granted by the court — forced the pathologist to swab for DNA evidence around the throats of the girls.

After noting it’s “extremely rare” for a defense team to inject itself into the early stages of an investigation, Rodriguez says: “They are trying to gather whatever physical evidence they can to show that the death of the girls was at the hands of the mother.”

He says he can understand the urgency from Chris’ side to make that request. “The reason that the defense is taking this position is that, once that evidence is gone, it’s gone forever,” he says.

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But he’s also somewhat skeptical about the angle. “What they’re looking for is called ‘touch DNA,'” he says. “That’s not really going to tell you anything, because you expect a small child to have their parents’ DNA (on them) just from daily life. There’s a lot of touchy interactions, especially between a mom and two girls she takes care of.”

Will He Take a Polygraph?

Even if Chris’ attorneys follow that line of defense, it doesn’t necessarily mean Chris would be found innocent, Rodriguez says. It eventually still could result in a conviction, but on a potentially lesser charge and with a lighter penalty.

“One of the interesting things to see in this case is whether or not he’s going to take a polygraph,” he says. “If he is very serious about what happened, and he is guilty of only one homicide, that takes it from first-degree murder to manslaughter under a ‘heat of passion’ theory — which is a huge difference in sentencing between one count of manslaughter versus three counts of murder.”

The allegation that Chris may have concealed the deaths for several days also makes the strategy of blaming the wife a risk, says Rodriguez.

Shan’ann Watts
| Credit: Shanann Watts /Facebook

Chris gave media interviews appealing for the safe return of his wife and daughters after a family friend reported them missing on Aug. 13 — despite, according to the arrest affidavit, having loaded all three bodies into his work truck and driving to the work site where he allegedly buried Shan’ann and dumped the two girls.

“His credibility is rightfully questioned,” says Rodriguez.

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“The normal thinking is, look, if someone kills your children and you react by killing them back, it’s not something you’re going to necessarily be embarrassed or ashamed of, or try to hide,” he says. If Chris did indeed try to hide it, a prosecutor could argue that it shows “further evidence of his guilt,” Rodriguez says.

“There are two very important things in this case,” Rodriguez says. “One is the physical evidence and the biological evidence. Number two is, how he testifies in court and whether or not he is properly cross-examined.”

“If his defense attorneys can prepare him properly and have him testify and survive cross-examination, he’ll go home,” Rodriguez says. “If not, he’ll spend the rest of his life in prison.”

• With reporting by CHRISTINE PELISEK