The FBI and Tennessee Bureau of Investigation have been called in to assist local cops with a disturbing and “deeply saddening” investigation where a mother, father, grandmother, and 15-year-old were all found dead this week by authorities probing an abandoned baby case reported hours earlier.

Local District Attorney Danny Goodman Jr., of the 29th Judicial District, told Law&Crime on Wednesday that the child from the abandoned baby investigation, a 7-month-old, is related to the family and is the son of Matthew Wilson and Adrianna Williams, who were found dead Tuesday at around 8 p.m. with the infant’s grandmother, Cortney Rose, and his maternal teen uncle, Braden Williams, according to Goodman.

“TBI is interviewing individuals who may have information,” Goodman said, noting that “several people” are being questioned.

“This is not something that would just be a random event that should concern the average citizen,” Goodman told Law&Crime. “This is a situation where I don’t think there needs to be a lot of public concern about an incident like this happening to someone else. There will be an explanation for it at a later time.”

Federal investigators and TBI agents were on the ground Wednesday aiding police with the “tragic” death investigation after the bodies were found Tuesday in Lake County along Carrington Road in Tiptonville, according to TBI officials.

The abandoned baby probe stemmed from the discovery of Wilson and Williams’ 7-month-old in a “random individual’s front yard” on Tuesday at around 3:10 p.m., police say. A “dark-colored minivan or a white mid-size SUV” was reported to have dropped off the infant in a car seat, which led cops to Lake County and the bodies being found roughly five hours later after authorities identified the child’s parents, per Goodman.

“TBI agents, with the assistance of the FBI and the Lake and Dyer County sheriff’s offices, continue to investigate the deaths of four individuals found Tuesday along Carrington Road in Tiptonville,” TBI Communications Director Josh DeVine told Law&Crime. “At this time, the investigation remains active and ongoing,” DeVine said.

Dyer County Sheriff Jeff Box posted a statement on Facebook saying Tuesday was a “deeply saddening day” for his community following the discovery.

“We are committed to uncovering the truth and ensuring justice is served,” Box said.

Lake County Sheriff Bryan Avery informed residents on his office’s Facebook page that the TBI was leading this case “with the highest level of diligence and professionalism” possible.

“This remains a very active and ongoing investigation,” Avery said. “Our thoughts and prayers are with the friends, families, and the entire community impacted by this tragic situation. We know this is a difficult time, and we stand with you.”

TBI officials would not say Wednesday whether any criminality was suspected or suspects being sought in connection to the death investigation, nor would Goodman. Police referred all requests for comment by Law&Crime to the bureau. The FBI did not respond to Law&Crime’s requests for comment.