Was Russell Yates Culpable?

The state of Texas has already prosecuted Andrea Yates for what she did, she's serving life in prison for killing her children, but it may now be going after her husband, Russell, for what he may not have done.

CBS News Correspondent Maureen Maher reports that Harris County District Attorney Chuck Rosenthal has assigned a prosecutor to look into whether there's evidence of possible culpability in the drownings of the couple's five children.

To call it an "investigation" would be too strong, Rosenthal said.

Rosenthal said his office began looking into Russell Yates at the urging of e-mails sent to his office since his wife drowned the couple's five children in the family bathtub last June 20.

"We're looking into it, because we've been asked to look into it," Rosenthal said.

Charges Russell Yates might face could include crimes of omission and child endangerment.

Andrea Yates, 37, was convicted of March 12 on two counts of capital murder. Although prosecutors acknowledged Yates was mentally ill, the jury decided she knew her actions were wrong.

Prosecutors have questioned why Russell Yates left his wife alone with the children. The father has said he thought his wife would be fine with the children for the hour between when he left for work and his mother arrived to help out.

Yates has said he blames doctors and hospitals for not properly treating his wife. He said a doctor changed his wife's prescription two days before police arrived at the family's home after Andrea Yates called 911.

"If they had given her the same medicine that worked before, if they left her in the hospital until she was well, any number of things in her medical treatment - and this never would have happened," Yates said.

He has also blamed his wife for not disclosing her delusional thoughts of the devil.

"One thing I'm not happy with is the fact that she never told me she had any thoughts of harming the children," Yates said.

But a psychiatrist who treated Andrea had warned him - if Andrea got pregnant again - the post-partum psychosis that twice drove her to attempt suicide would likely return with a vengeance.

In an earlier interview with CBS News, Andrea's family accused her of ignoring what they say were obvious signs of her mental illness.

"The people around you have to pay more attention and look for the signs and Andrea definitely had the signs," said Andrea's sister, Michele Freeman.

Russell Yates' attorney, Edward Mallett, said Monday he was confident any probe of his client would show he is innocent of any wrongdoing.

"Russell is innocent of any wrongdoing. He's a victim," Mallett said. "It's a tragedy that Rusty now has to defend himself after standing by his wife."

Legal analysts say getting a conviction against her husband may prove impossible because prosecutors presented such a strong case that Yates knew what she was doing when she killed her kids.

"For them now to turn around and say Russell Yates knew - or should have known - that the children were in trouble may be a stretch," CBS News Legal Analyst Andrew Cohen said.

Prosecutors admit getting a conviction would be tough.

"It's not necessarily criminal to be a bad husband," District Attorney Rosenthal said.