By: CBS News

May 27, 2016

HOBE SOUND, Fla. -- Crime scene technicians unearthed partial remains believed to be a missing south Florida mother after her ex-husband, who is charged with her murder, led them to the place where he said he buried her in an acid-filled barrel in a shallow grave in the Hungryland Wildlife Management Area, reports CBS affiliate WPEC.

The remains that are likely U.S. Air Force veteran Tricia Todd were located 19 miles away from her Hobe Sound home and just outside investigators' original search area, a 15-mile perimeter near Todd's home.

"(The grave) is nothing more than a simple hole maybe three feet deep. The body was in a container," said Martin County Sheriff William D. Snyder at a press conference at the preserve on Thursday evening.

Snyder said the body was mutilated and appeared to have been dismembered with a chainsaw.

Snyder described the container as filled with fluid that a Hazmat team on the scene believed to be acid and said DNA testing will confirm whether the remains are, indeed, those of Tricia Todd.

On Wednesday, the Martin County Sheriff's Office announced that Todd's former husband, Steven Williams, confessed to her murder. In exchange for pleading no contest to second-degree murder and receiving a sentence of 35 years in a state prison, Williams agreed to lead them to the body, officials say.

Officials aren't sure where Todd was killed, Snyder said Friday, but believe the murder likely happened in a different area than where her remains were found. He said officials likely wouldn't be able to determine the cause of death without uncovering more remains.

Cadaver dogs were alerting over a "fairly extensive area" where human remains or blood may have been located, Snyder said, but as of Friday morning more remains hadn't yet been found. Crews were continuing the search.

"We will not be satisfied until we've discovered all of her remains," Snyder said.

Assistant state's attorney Tom Bakkedahl said he believed the murder was premeditated and was initially against negotiating the plea deal with Williams, but said he did so because of the wishes of Todd's family to locate her remains and seek closure.

"It's an unfortunate reality that yes, in this business, you have to make a deal with the devil - and I made a deal with the devil," Bakkedahl said.

Bakkedahl described Williams' demeanor as "cold - without feeling - no remorse - no sympathy."

"It actually shocks the conscience to know you're walking the streets with people like this," he said.

Because Williams led detectives to only part of Todd's remains, however, Bakkedahl said the plea agreement could be in jeopardy.

Tricia Todd, a 33-year-old hospice nurse, has been missing since April 27 when she did not pick up her daughter, 2, from a babysitter.

Williams, a 30-year-old U.S. airman stationed in North Carolina, reportedly initially told police he had been caring for the child, but when Todd didn't show up, he dropped the girl off with the babysitter and returned to his base. Martin County detectives traveled several times to North Carolina to interview him. At a Wednesday press conference, Snyder said the initial story Williams told police had "gross inconsistencies... which only got worse with time."

Williams became a suspect in Todd's murder when he was seen on surveillance video driving her truck after she went missing. Williams later told authorities that she died during a physical altercation during which she hit her head. Williams allegedly changed his story multiple times before admitting to investigators he pushed Todd "for the final time" during an argument over money, reports WPEC, citing an arrest affidavit.

Williams said Todd became "increasingly aggressive" and "got into his face" before he said he shoved her. He told police Todd "fell and hit her head on something and did not get up," and admitted disposing of her body.

Snyder has said that he believes Todd was killed near her young daughter. The child is in the care of family.

The Air Force said in a written statement released to the station they are "cooperating fully with civil authorities in this case." Williams was assigned as a field training detachment instructor with Detachment 1, 372nd Training Squadron, according to WPEC. Though located at Seymour Johnson Air Force Base, N.C., the unit is attached to the 82nd Training Wing, Air Education and Training Command, with headquarters at Sheppard Air Force Base in Texas.

Todd had been stationed at Shaw Air Force Base in South Carolina. She reportedly worked in food services before her discharge in 2008.

A statement on a Facebook page dedicated to the search for Todd Wednesday said the news of Todd's death is "beyond heart-breaking and indescribably painful."

Her disappearance launched one of the largest searches in recent Martin County history and involved hundreds of deputies and volunteers who canvassed thousands of acres in search of her.

"Tricia Todd was a real person - she was a living human being, and a mother, and a hospice nurse, and a beautiful woman who certainly deserved to live," Snyder said Friday. "Death comes to everyone - sometimes it's unexpected - but in a case like this when it's murder, it's heinous beyond description."

By: Associated Press

May 25, 2016

HOBE SOUND, Fla. (AP) -- The ex-husband of a missing Florida woman has been arrested on second-degree murder and child neglect charges.

During a news conference Wednesday morning, Martin County Sheriff William Snyder said 30-year-old Steven Williams confessed to killing Tricia Todd in April. The Air Force airman was arrested Tuesday in North Carolina.

She was last seen at a Publix supermarket on April 26 and reported missing the next day.

Snyder wouldn't say how Todd died. Her body hasn't been found, but Snyder says officials are redoubling their efforts to find her remains.

The sheriff's says the lack of a body won't stand in the way of prosecution.

Snyder says Todd's 2-year-old daughter was there when her mother was killed. She is now living with family members.

Williams is being held without bond and records don't indicate whether he has a lawyer.