SAN ANTONIO – A search of a southeast Bexar County landfill for evidence in the disappearance of Suzanne Clark Simpson was linked to a sealed search warrant, according to sources close to the investigation.

The warrant was signed Saturday after being filed by the Texas Department of Public Safety, sources told KSAT.

The Texas Department of Public Safety told KSAT that the dump is one of four areas they searched in connection with Simpson, an Olmos Park mother of four and real estate agent who was seen for the last time on Sunday October 6.

Texas DPS asked KSAT not to reveal the exact location due to the ongoing investigation.

According to Texas DPS, they finished their search Monday but will return Tuesday.

Sealed warrants are common in federal cases but are rarely used in county cases. The seal can remain in place for up to 31 days and can only be used if an attorney establishes in court that public disclosure of the contents of the case would harm the case.

Suzanne Simpson’s husband, Brad Simpson, was arrested Wednesday, Oct. 9, and booked into the Kendall County Jail on charges of assault causing bodily injury, domestic violence and unlawful restraint, records show. The next day, he was transferred to the Bexar County Jail, where he remains on $2 million bail.)

Investigators searched the couple’s home in and around Olmos Park on Wednesday, but declined to say what evidence, if any, was found.

Multiple agencies searched an area along Interstate 10 in Boerne on Friday. A search party was seen in the 33000 block of I-10 near Highway 87, about a mile from where Brad Simpson was arrested.

Authorities did not say whether anything significant was discovered during the searches.

Learn more: What We Know About Missing Olmos Park Woman Suzanne Clark Simpson