Mo. mother likely killed 3 daughters, then herself, based on email, authorities say

(CBS/AP) DE SOTO, Mo. - An email sent by a mother to her estranged boyfriend indicates she fatally shot her three young daughters before killing herself in rural eastern Missouri, authorities said Thursday.

Jefferson County Sheriff Glenn Boyer said all four were found shot in the head early Thursday outside the ex-boyfriend's home near De Soto, about 45 miles south of St. Louis.

CBS affiliate KFVS identifies the three young girls as Faith Ehlen, 22 months, Autumn Cochran, 10, and Alyssa Cochran, 11. Their mother was identified as 32-year-old Lisa Cochran.

Cochran was reportedly found dead on steps leading to the porch. The girls were found inside a van in the driveway.

Boyer said an email sent by the mother to relatives and her exboyfriend led investigators to believe she killed the children, then herself. He said the email was sent to the ex-boyfriend after 8 p.m. Wednesday.

What appeared to be a newly purchased 12-gauge shotgun was found near the woman, but Boyer said it wasn't yet known who owned the weapon.

"At this point in time, it looks like it's going to be a murder-suicide," he said.

Detectives were questioning the ex-boyfirend but Boyer said he is not considered a suspect.

The ex-boyfriend called authorities shortly after midnight when he spotted the mother's van in the driveway at his home, Boyer said. The woman had an order of protection against the boyfriend obtained on Aug. 13. Because of that order, he didn't want to approach her van, instead driving to a nearby highway to call the sheriff's department rather than stay home and confront her, Boyer said.

Boyer said the man was the father of the 1-year-old girl. The couple previously lived together but the woman recently had been living with relatives. The other two girls were from a previous marriage.

More on CrimesiderSeptember 6, 2012 - Mother, 3 daughters found shot to death in Missouri