A 17-year-old boy shot and killed a 14-year-old girl and then himself at a house where he was dog-sitting Saturday evening.

The Pinellas County Sheriff’s Office said that Hector Pfeiffer invited three other teens — two girls and an 18-year-old man — to the home of 26-year-old Derek Pobuta, where he was staying to watch the dog while the homeowner was out of town. The teens came over at about 4:00 a.m. on Saturday and “consumed alcohol, marijuana, and cocaine throughout the day.”

Deputies said Pfeiffer met the two girls on a social media app about a month earlier. He was already friends with the 18-year-old.

In the course of the day, Pfeiffer took out a firearm belonging to Pobuta and soon all four of the teens “began playing with the firearm and taking photos with it.”

Eventually, the drug- and alcohol-besotted teens got into an argument over “a consensual sexual encounter Pfeiffer had,” which upset him. Detectives say he walked over to where 14-year-old Sayuri Jade Ruiz was talking with the other girl and shot Ruiz in the head, then shot himself in the head.

Deputies received a 911 call just before 9 p.m. and arrived to find Ruiz dead. Pfeiffer was still breathing, however, and was taken to a hospital, where he died.

The investigation is ongoing and it’s not clear if any charges will be filed, given that the perpetrator killed himself. The medical examiner is conducting an autopsy.

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