A nearly five-hour standoff between an armed child pornography suspect and Polk County sheriff’s deputies ended on Tuesday afternoon when the suspect fatally shot himself near the Christina Animal Hospital just south of Lakeland.

PCSO crisis negotiators tried to persuade Marquis Lynn Baker, 45, of Jacksonville to surrender peacefully. However, Baker, who was armed with a .40 caliber handgun, remained barricaded in his gray 2012 Chevrolet Impala near the veterinary clinic at 6800 N. Church Avenue, on the Lakeland-Mulberry line off Highway 37.
“We negotiated with him for about four hours before he shot himself, despite our hostage negotiators’ work,” Polk County Sheriff Grady Judd said. “He never threatened us.”
Judd said Baker still had vital signs after the shooting, which happened in front of multiple law enforcement officers.
“We performed emergency, life-saving measures, but his wound was too severe to survive,” Judd said.
Baker was a U.S. Marine who worked as a utilities chief and engineer equipment quality assurance inspector at the Marine Corps’ Blount Island Command. He was arrested at the base on Oct. 12 and charged with 11 felony counts of possession of child pornography for having at least 110 images between November 2019 to January 2021.
He was released on $25,000 bond on the condition that he wear a GPS ankle monitor, have no contact with minors and not use the Internet.
An ambulance, escorted by a deputy’s patrol car, left the animal clinic at 3:30 and headed north. Judd said Baker died on the way to the hospital.
PCSO spokesman Brian Bruchey said in an emailed statement that no deputies fired on the suspect, nor were any deputies injured.
The standoff began around 10:30 a.m. when PCSO deputies became aware that Baker, who was in Bartow, had a warrant for his arrest from Duval County for failure to appear on the child pornography charges.
Judd said he was listed as a missing person after rejecting a plea deal and telling his attorney he wasn’t going to prison.
In a news release Wednesday morning, Bruchey said deputies followed Baker’s car for about five minutes until he turned west into the parking lot of the animal hospital. He continued down an unpaved access road on the east side of a set of railroad tracks behind the clinic, stopped his car and put the handgun to his head.
“Deputies continually communicated with Baker during the standoff trying to get him to surrender, and even provided him with a cell phone to make it easier to keep the dialogue going,” Bruchey said in the release.
However, at about 3:20 p.m., he fired a single bullet to the left side of his head. He was pronounced dead at 3:50 p.m.
During the standoff, more than two dozen law enforcement vehicles surrounded Baker as he sat in his car with the air-conditioner running.
Vehicles on the scene included patrol cars, ambulances, K-9, SWAT, command center, unmarked and bomb squad units. At least 20 were around the veterinary clinic. Half a dozen more were on a paved access road on the west side of the railroad tracks, behind the clinic. In addition, the PCSO helicopter circled overhead for hours.

Temperatures on Tuesday reached at least 100 degrees at the scene. Judd said they were trying to determine if the car had OnStar so they could turn it off as a way to force him out.
“We’ve got him blocked in where he can’t leave and is not a threat to the public,” Judd told LkldNow about two hours into the standoff.
The veterinary clinic is across the street from several fast food restaurants and a Walmart Supercenter. Throughout the ordeal, cars continued to turn left onto Carter Road and the Walmart store remained open and busy with the back-to-school shopping season in full swing.
One southbound lane of Highway 37 was closed during the standoff, but the other remained open. Both northbound travel lanes were open, however Polk County Fire Rescue trucks blocked the northbound turn lane into the clinic.

LkldNow editor Cindy Glover contributed to this report.