TAMPA — Eight hundred mushy text messages between a 39-year-old sheriff's deputy and his 15-year-old "love muffin" failed on Friday to convince a jury that the deputy and the high school sophomore actually had a sexual affair.

Lacking was physical evidence. William Todd Best, a 10-year veteran of the Hillsborough County Sheriff's Office, was guilty only of "stupid, inappropriate text messages," his attorney told jurors. They agreed that the state hadn't proved otherwise.

The jury acquitted Best of four counts of lewd and lascivious battery of a minor. The acquittal spared Best a possible 15-year prison sentence.

Surrounded by jubilant family members, the former deputy from Riverview declined to comment. Neither the girl nor her parents were present.

Jurors had deliberated six hours before asking Circuit Judge Chet Tharpe to let them rehear testimony by a crime lab technician who had searched for Best's bodily fluids on swabs taken from the girl after an alleged sexual encounter.

After hearing once more that the technician found no semen, jurors returned an hour later with their verdict.

During the three-day trial, the girl had described an affair in the spring of 2011 that began after her mother met Best at a Department of Highway Safety and Motor Vehicles office where he moonlighted. The mother briefly dated him.

Among the strangest of the text exchanges between Best and the girl was one in which she asked him: "Are you sure you didn't like kissing my mom more than me?"

The deputy's reply: "You're the best, baby."

The girl read hundreds of the text messages to the jury. Few were overtly sexual, though several hinted at sex. Most were tediously adolescent-sounding.

In closing arguments Friday, Assistant State Attorney Courtney Derry acknowledged that the case had problems. The girl had admitted lying to investigators, making up a story about a nonexistent condom. She also gave conflicting statements during a rape examination, where no evidence of a sexual encounter was found.

But, Derry said, "You can't ignore 800 texts in 11 days. There are no inconsistencies in the 800 texts."

In 50 of them, Best told the girl he loved her.

Both talked about yearning for her 18th birthday. The girl is now 17.

Best's attorneys said the texts were "wishful thinking."

John Barry can be reached at (813) 226-3383 or jbarry@tampabay.com.