A horrible, gruesome tragedy unfolded in Maryland on Aug. 18. Antonio Williams was trusted to look after his little sister and two cousins. Instead, the 25-year-old man allegedly murdered these innocent girls.

Three young lives were tragically cut short, all in a senseless act of murder. Antonio Williams, 25, was arrested on Aug. 18 for the deaths of his sister, Nadiara Janae Withers, 6, and cousins Ariana Elizabeth Decree, 9, and Ajayah Royale Decree, 6 according to The Washington Post. Antonio’s mother, Andrena Kelley, left him to babysit the children while she worked the overnight shift. Instead, he allegedly stabbed the three of them. When Andrena returned to her home in Clinton, Maryland, she found the girls in a basement bedroom, all suffering from apparent stab wounds. First responders found all three of the girls dead on the scene, and Antonio was taken into custody.

“The preliminary investigation reveals Williams had sole care and custody of the children at the home overnight into Friday,” police said in a news release, according to ABC 7. “He has confessed to killing the victims.” He has been charged with three counts of first-degree murder and three counts of second-degree murder. He is being held without bail. The Decree sisters were visiting from Newark, New Jersey for the summer, as they are the daughters of Andrena’s cousin, according to the New York Daily News.

A 2-year-old girl – another of Antonio’s other sisters – was in the home at the time but was left unharmed in the carnage. The crime scene was, as police spokesperson Jennifer Donelan said, “one of the most difficult that our officers have arrived on.”

What could have driven Antonio to commit such a horrific act? Sadly, despite his reported confession, his motive remains unclear. “We have many answers, but unfortunately we don’t have all of them at this point,” Prince George’s County police Capt. Anthony Schartner said during a press conference, adding that his team was only hours into their investigation into this unthinkable tragedy.

VIDEO: Antonio Williams walk shot after he confessed to murdering his sister & cousins: https://t.co/xchfOlQd4y (via @PGPDNews) pic.twitter.com/JQTlxWEIRf — FOX 5 DC (@fox5dc) August 19, 2017

“This is horrific,” James Pinkey, a neighbor told The Washington Post after hearing the “earthshaking news.” James said he was going to stay at home on Aug. 18 to protect his 13-year-old daughter as police continued their investigation. “My heart is heavy. How could you live with yourself [after] committing such an evil act?”

Our thoughts are with the families and friends of the victims during this heartbreaking time of loss.