Tennessee officials are struggling to explain why an apparently loving mother shot her four adopted children to death before taking her own life. 

Cynthia Collier’s adult biological son called 911 shortly after 6 p.m. Monday after he returned home from work and found Collier, 55, and his four youngest siblings dead of gunshot wounds in their Columbia home. Evidence found at the scene indicated Collier committed the killings, officials said Tuesday during a news conference. 

“There was some information that was left -- it was very brief and vague -- that would indicate that it would be murder-suicide,” Maury County Sheriff Bucky Rowland said. 

Rowland on Tuesday identified the dead children: Kaileigh Lin, 17, Lia Lin, 15, and 14-year-olds Meigan Lin and Bo Li. Court records indicate the children were adopted from China, The Tennessean reported.

Rowland did not specify where in the house the children were killed, but he said there were multiple crime scenes in the home. Investigators recovered two weapons believed to have been used in the slayings.

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The sheriff described Collier as a stay-at-home mother who homeschooled her adopted children. Fox17 in Nashville reported that Collier had properly registered with the state to teach her children and submitted curriculum and attendance records. 

The children did not participate in extracurricular activities in Maury County, and neighbors said the family kept to themselves, the news station said. 

Rowland said the motive for the shootings remained elusive. By all accounts, Collier was a “very loving mother, with the exception of this one incident.”

“This appears to be a loving home,” the sheriff said. “It’s an immaculate home and a very loving family, so a motive would be very important to know what would lead someone to do this to her loved ones.”

Watch Rowland’s entire news conference below.

Besides her adopted children, Collier had three adult biological children -- two sons and a daughter. The Tennessean reported that Collier and her long-estranged husband, Randall Collier Sr., began divorce proceedings in March after 36 years of marriage. 

They attempted to reconcile in May, according to court records obtained by the newspaper, but it was unclear how the reconciliation was going. Randall Collier did not live in the house where the homicides took place. 

In sworn statements the four youngest children gave during the divorce proceedings, they asked to continue living with their mother, The Tennessean reported. The teens said they barely knew their father. 

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The three biological Collier children also gave statements in which they said their relationship with their father had also been a strained one, including their interactions before Randall and Cynthia Collier’s 2007 separation, the court records said.  

Rowland said Randall Collier and other family members were interviewed during the investigation into the shootings, but the department has no evidence that the crime was anything other than a murder-suicide. His department had no record of any domestic calls to the home prior to the son’s 911 call Monday. 

The sheriff asked the public to keep the victims and their family in prayer, as well as the deputies and other first responders who witnessed the crime scenes in the Collier home. 

“We deal with difficult situations, we deal with carnage each and every day, but the magnitude of this, it was more than what we’re used to on a day-to-day basis,” Rowland said. 

Rowland said it is difficult for law enforcement agencies to deal with potential issues involving mental illness. He encouraged those in crisis to seek help.  

“Don’t be embarrassed,” the sheriff said. “Don’t hesitate. Always try to seek professional help any time that you feel a loved one or yourself may be suffering from that.”