Even though maybe they've been tirelessly toiling in the background all these years, it seems like investigators only start trying again to solve the 25-year-old Kristin Smart murder case every five years. And with the anniversary approaching in May, San Luis Obispo County sheriff’s officials have just announced the arrest of who they now say is their "prime suspect," 44-year-old Paul Flores.

Also arrested was Flores's father, Ruben Flores, now 80 years old, as an accessory.

The arrests of the Floreses comes a year and two months after authorities executed new search warrants at four locations in California and Washington State, including Flores's San Pedro, California home, and the two homes of his parents in Arroyo Grande. And the arrests come a month after new searches were conducted at Ruben Flores's home, including a search under a back deck and in the backyard with ground-penetrating radar and cadaver dogs. As KSBY reported, police and the dogs appeared to be interested as well in an old Volkswagen Cabriolet that was on the property.

Back in 2016, Paul Flores was still being called a person of interest in the 20-year-old case, when authorities conducted several digs on the on the Cal Poly campus. The case began as a missing persons case when Smart disappeared after an on-campus party on Memorial Day Weekend in 1996. 19-year-old Smart, who was from Stockton, was walking home to her dorm with three friends around 2 a.m. when she and Flores left the other two. Flores has claimed for over two decades that he went into his dorm and left Smart to walk by herself to hers, but he was the last person to have seen her alive.

Smart was legally presumed dead in 2002, and the case has continued to confound investigators. As reported many times previously, Flores never quite incriminated himself, however he did say something suspicious during an initial interview with San Luis Obispo County district attorney’s officials back in 1996. He reportedly "pulled his arms into his T-shirt, scrunched over at the waist in his chair and lifted his feet off the floor, as if moving toward a fetal position" and said, "If you are so smart, then tell me where the body is."

At 2 p.m. Tuesday, sheriff's department officials were set to give a press conference and potentially reveal more about what was discovered on Ruben Flores's property last month that led to these arrests, after so many false starts.

Stay tuned for an update following the presser.

Update: San Luis Obispo County Sheriff Ian Parkinson said at the press conference that Flores had been charged with Smart's murder, and that they have had evidence since late 2016 that led them to consider Flores the prime suspect. Parkinson did not reveal what had been found in recent searches on the Flores property, and those search warrants remain sealed. He did reveal that the Sheriff's Office obtained a warrant to monitor the Floreses' cellphone communications, and said that physical evidence had been found at Ruben Flores's home — though Kristin Smart's remains have still not been found. [KTVU]

Related: Authorities Dig Up Cal Poly Campus In New Search For Kristin Smart, Missing Since 1996