TUCSON, Ariz. – Investigators in Arizona returned to the home of NBC "Today" co-host Savannah Guthrie's mother on Wednesday afternoon as they continue to aggressively seek tips.

Deputies with the Pima County Sheriff's Department were seen back at Nancy Guthrie's home on Wednesday afternoon, putting up yellow crime scene tape. K-9s were also brought to the home, but it's unclear why law enforcement returned to the home four days after Nancy Guthrie's disappearance. The Pima County Sheriff's Department said in a tweet it was "conducting follow-up' at the home, offering no details.

Several people who appeared to be law enforcement also showed up at Savannah Guthrie's sister Annie Guthrie's home on Wednesday. The home is just a few miles from Nancy Guthrie's home. It's unclear why they were there, but they brought some equipment inside.

Nancy Guthrie, 84, was last seen at her Tucson residence at around 9:30 p.m. Saturday, according to the Pima County Sheriff's Department. While officials didn't immediately elaborate on the circumstances of her disappearance, Sheriff Chris Nanos said on Monday that "we do, in fact, have a crime." A law enforcement source told Fox News Digital that there were "blood drops" leading from the entryway outside down the house's pathway towards the driveway. 

Nanos said Nancy Guthrie didn't attend her Sunday church service, adding that her family was notified about the absence by a churchgoer. Officials said family members went to Nancy Guthrie's home at around 11 a.m. and spent some time looking for her. Her family called 911 at around noon. Nancy Guthrie had dinner with her daughter Annie and son-in-law, Tommaso Cioni, on Saturday evening, Nanos told White House also commented on her disappearance, writing: "The search for Savannah Guthrie’s mother, Nancy Guthrie, is ongoing, and authorities are requesting assistance from the public. Anyone with information is urged to contact 911."

"Our prayers are with the Guthrie family as we hope for Nancy’s safe return home," the White House posted.

Savannah Guthrie spoke out on Instagram in a post on Monday, writing "We need you."

"We believe in prayer. We believe in voices raised in unison, in love, in hope. We believe in goodness. We believe in humanity. Above all, we believe in Him," she wrote. "Thank you for lifting your prayers with ours for our beloved mom, our dearest Nancy, a woman of deep conviction, a good and faithful servant. Raise your prayers with us and believe with us that she will be lifted by them in this very moment."