Cheryl Coker, 46, has been missing since October 2, 2018

Cheryl Coker
| Credit: Cheryl Coker Missing October 2nd 2018 Riverside, OH/Facebook

More than four months after the disappearance of an Ohio woman, police have named her estranged husband as the suspect.

Cheryl Coker, 46, has been missing since October 2, 2018, when she returned home after dropping off her 15-year-old daughter at school.

On Tuesday, Riverside police identified William “Bill” Coker as a suspect after officials uncovered evidence that may prove Cheryl vanished under suspicious circumstances, thus reclassifying her case as a homicide, according to WDTN. Police do not believe Cheryl is alive.

Riverside Police Det. Travis Abney told reporters Tuesday that William is the only suspect and has “been reluctant” to take a polygraph test, WDTN reports.

William denied the allegation he was involved in his wife’s disappearance, telling WHIO on Tuesday, “I’ve never in my entire life hurt anyone,” adding, “She was behaving in some risky behavior right before she disappeared and I haven’t really been willing to put that out there.”

Cheryl’s sister, Margie Keenan, reported her missing after her niece, who is Cheryl’s daughter, called to inform her that she hadn’t seen or heard from her mother. “The pit of my stomach, something hurt, and I knew something wasn’t right,” Keenan told WHIO.

Eleven days before she was reported missing, on Sept. 21, Cheryl filed for divorce from her husband of 19 years, seeking spousal support and custody of their daughter.

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Detectives said Cheryl had left her home early morning to take her daughter to Stebbins High School and drove back home where Cheryl spent several minutes sharing posts on Facebook. “About 7:45 that morning, pretty much everything electronically with her just stopped,” Abney said, according to video from Tuesday’s press conference.

Also on Tuesday, police released surveillance video from Oct. 2 that shows Cheryl’s 2016 Toyota Highlander driving into the Kroger parking lot, which is less than a mile from her home, at 10:52 a.m. The footage shows an unidentified person, who is dressed in all black with their sweater hood pulled up, exiting the vehicle and walking through the parking lot.

Shortly after the unidentified person was spotted at the time, a citizen called 911 to report a suspicious white male dressed in all black with his hood pulled up.

Another surveillance video, seen on Spinning Middle School’s four exterior cameras and captured on Oct. 2, shows the same suspicious male walking toward the Coker residence.

The next day, on Oct. 3, Cheryl’s family located her vehicle with her purse and cell phone locked inside. “She doesn’t go anywhere without that phone,” Keenan told WHIO.

Abney hopes by releasing the surveillance footage, new leads will be submitted and that someone who may have seen something will speak with investigators.

In addition, police uncovered text messages from William and his current girlfriend that allegedly raised suspicion.

The girlfriend told police Cheryl texted her on Aug. 28 asking that if Cheryl “were to die or wasn’t in the picture, would she pursue a permanent relationship” with William. “It was reportedly sent by Cheryl but we’re not 100 percent convinced that she actually did send that,” Abney told reporters on Tuesday, according to WHIO.

Then on Sept. 24, William texted Cheryl, “Thanks for putting the nail in my coffin,” and Cheryl later texted a coworker that same day: “I will be in tomorrow if I’m not dead.”

It was not immediately clear if William has retained an attorney who could comment on his behalf.

A spokesperson for the Riverside police did not immediately respond to PEOPLE’s request for comment.