A senior found dead inside his home in the town of Center has prompted an investigation by the Colorado Bureau of Investigation.

The 78-year-old is believed to have last been seen alive Friday and was found dead inside his kitchen Tuesday morning, according to a news release from the CBI. The time of death is currently undetermined.

Center is a statutory town located near the Great Sand Dunes National Park and Preserve in Saguache and Rio Grande counties.

Authorities found his body after construction workers building a new garage at the man’s home contacted police and told them the man hadn’t been seen or spoken to for a couple of days. The last known contact was Friday, when family members spoke to him on the phone, and the workers saw him.

The death is being investigated as “suspicious.” The exact cause of death will be determined by the El Paso County coroner later this week, according to the release.