Gainey has several prior arrests for assault and domestic violence.

Inmate Name:  GAINEY, WILLIAM  MONROE      
Booking Number: 2015-010703 
Booking Date: 5/30/2015 
Race: W    Sex: M    DOB: 12/6/1953 
Height: 602     Weight: 210 
Location: SOUTH COUNTY JAIL MEDICAL 
Arresting Agency: POLK COUNTY SHERIFF 

After intense around-the-clock investigation, interviewing witnesses who came forward, and conferring with the State Attorney’s Office, the PCSO Traffic Unit has additionally charged 61-year-old Polk County Jail inmate William Monroe Gainey with two counts DUI Manslaughter (F-2), two counts Vehicular Homicide (F-2), and one count DUI with Property Damage (M-1).

Sheriff Grady Judd Polk County Fla.

The charges were filed late last evening, June 1, 2015. He remains in the Polk County Jail.

“Thanks to the media coverage of this crash, and our social media fans, we were able to identify two witnesses who came forward to help us piece together the timeline of William Gainey’s actions leading up to this horrific event. Furthermore, thanks to the computer equipment in his truck, we know that he accelerated from 73 to 80 MPH just before impact, and made no attempt to brake. Because of his recklessness and wanton disregard for human life, he killed a little boy and his father, who were simply stopped for a red light on their way home. The thought of that horrifies me. I hope he spends the rest of his life in prison.” – Sheriff Grady Judd

From Bay 9 News Now

LAKE WALES — Charges have been filed in the crash Friday night in Winter Haven that killed a Lake Wales man and his 4-year-old son.

William Monroe Gainey, 61, of Lake Wales was charged Monday night with two counts of DUI manslaughter, two counts of vehicular homicide and one count of DUI with property damage. He was already being held in the Polk County Jail on a domestic battery charge stemming from an altercation before the crash.

Investigators say air bag module data from Gainey’s 2014 Chevrolet Silverado shows the pickup truck was traveling at 80 mph and accelerating when it slammed into the back of a 2010 Ford Focus at a red light on Cypress Gardens Boulevard. The driver of the Focus, Christopher Ivey, 38, and his young son Jayden were killed in the 10:30 p.m. crash.

Gainey was taken to Lakeland Regional Health, where tests showed he had a blood alcohol content of 0.74 percent and benzodiazepines (tranquilizers) in his system, investigators say.

According to the investigators’ timeline, Gainey got into an altercation at his home on Silver Spur Loop with his girlfriend’s son between 9:30 and 10:30 p.m. The son declined to press charges, but Gainey was charged with domestic battery against the daughter, who had attempted to intervene. The girlfriend told investigators Gainey had appeared “a little drunk” and “has been drinking more in the past four or five months when he started showing more depression,” the arrest affidavit says. ….MORE

Photo of Gainey being arraigned in court