VERDIGRIS, Okla. – A woman and her three children were discovered dead in their home in Oklahoma on Thursday evening in an incident that unfolded during an hours-long standoff. 

Law enforcement authorities suspect a murder-suicide, and the names of the victims have not yet been released.

The Associated Press reports that the chain of events began when a police officer noticed fireworks emanating from the garage of a residence in Verdigris, a suburb about 20 miles east of Tulsa.

Hunter McKee, spokesperson for the Oklahoma State Bureau of Investigation, told the AP that the officer sensed something was amiss and called for backup.

Upon closer inspection, the officer discovered a woman and two children locked inside the garage, along with what Police Chief Jack Shackleford described as a Roman candle firework. The woman revealed that she had taken another child to the home for a supervised visit, only to be confronted by an armed woman who seized the child and confined the woman and the two accompanying children in the garage.

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Multiple agencies, including a SWAT team from the Cherokee Nation, swiftly encircled the residence. Following a three-hour standoff with no response from inside the house, officers entered the home and found the adult woman and three children dead with gunshot wounds, the AP reports.

The children are believed to range in age from several months to around 11 years old. The nature of the relationship between the two women involved in the incident remains unknown at this time.