Boyfriend Arrested and Charged After 18-Year-Old Pregnant Kylee Monteiro Found Dead Weeks After Going Missing

After a pregnant teen vanished in Massachusetts, police uncovered a disturbing confession, a concealed burial site, and a murder charge against her boyfriend.

Kylee Monteiro, 18, had recently graduated from Attleboro High School and was 11 weeks pregnant when she was reported missing on August 7, 2025. Then, on Tuesday, August 19, her body was discovered in a wooded area behind her boyfriend's residence in Rehoboth, Massachusetts.

He has since been arrested and charged with her murder after allegedly confessing to killing her and showing investigators where to find her remains. Gregory Groom, 22, initially told police that Monteiro had arrived at his residence on August 6, after leaving a residential program.

According to prosecutors, she arrived by rideshare and was looking for a place to stay. Groom said they got into an argument about whether she could stay on his property. He claimed she ultimately left his house and that he had not seen or heard from her since. He contacted the police the following day to report her missing.

In the weeks leading to her disappearance, Monteiro had been living at a homeless shelter for pregnant women in Pembroke. Her relationship with Groom had been marked by instability and prior domestic issues. Faith Monteiro said her sister had experienced a physical altercation with Groom the night she went missing.

Faith told authorities that on the night her sister arrived at Groom's home, she texted her, stating, "He threw me on the ground, he pulled my hair, and strangled me. My phone is at 4% and if I die, it was Greg." She later sent Faith another text, saying that she was still attempting to stay at Groom's house.

Monteiro's last voice contact with anyone was the night of August 6, and her last text was the following day. A friend reported speaking to her shortly before she vanished. "She was like, 'I don’t feel safe right now, something's not right.' I tried talking with her after that, and she just stopped responding to me after that [sic]," the friend revealed.

A preliminary search of Groom's 25-acre property on August 14, which included K-9 units, did not yield any findings. On August 19, Groom returned to the police station for a second interview. That was when he admitted to getting into an altercation with Monteiro on August 6.

He said that during the argument, he pushed her, causing her to fall backward and hit her head. He also said that when Monteiro tried to contact someone, he threatened to knock her phone out of her hand. Police informed Groom they had obtained a search warrant and would dig if necessary.

At that point, Groom allegedly began to draw a map. Prosecutors said he indicated that the altercation had taken place behind a shed on the property where he often stayed. He then admitted to stabbing Monteiro twice in the neck and once in the chest, and that the blade broke off in her chest.

He then spent "several hours" digging a hole in the woods, approximately 20 yards from where the stabbing took place. He admitted to burying her body there and covering it with brush. Investigators found a pile of cut-down vegetation in the area described, and about five feet underground, they uncovered human remains consistent with Monteiro's.

Her body is currently with the medical examiner for identification and autopsy. Groom was arraigned on August 20 and is being held without bail. He faces charges of murder, assault and battery on a pregnant victim, assault and battery on a family or household member, and aggravated intimidation of a witness, juror, police, or court official.

His next court date is a probable cause hearing scheduled for September 10. Bristol County District Attorney Thomas M. Quinn said the investigation remains active and that the motive is not yet clear. He also stated that he met with Monteiro's family following the arraignment and encouraged them to be patient with the legal proceedings.

Monteiro had shared a pregnancy announcement on her Instagram account on July 18. The post featured a heart-shaped baby blanket and crayons arranged to spell "BABY GROOM." The caption read, "BABY GROOM! Coming to a big heart near you!😱 Mommy and Daddy already love you so much, Peanut.❤️🍼"

Her family said that Monteiro had been planning to enroll in welding school, and they were working to support her through her pregnancy. "She had great potential," family friend Piette shared. "When she found out she was pregnant, we were trying to work with her as best as possible to help her establish and have goals to be a mom and how to be a mom."