Mexico City police are closer to solving a high-profile kidnapping case that has tarnished the department’s reputation and forced the city’s top anti-kidnapping agent to resign.

Four people have been arrested in connection with the kidnapping and murder of 22-year-old student Norberto Ronquillo last month.

On Saturday, police arrested Daniel “B,” a cousin-in-law of the victim through his father, in Xochimilco. Police say Daniel is the owner of a grey Ford Topaz that was linked to the kidnapping and the receipt of a ransom payment.

Daniel “B” admitted to being the owner of the car but said he rents the car to a Uber driver and that when the crime took place, someone else was driving it. The driver, Óscar “N,” was arrested on Wednesday night.

Daniel “B” was also implicated in the 2015 kidnapping and murder of Édgar Carrasco Hernández, a distant cousin to Ronquillo. In a series of events similar to the Ronquillo kidnapping, Carrasco was kidnapped from his home in Morelos and his family received a call asking for a ransom.

After the family paid 500,000 pesos (US $26,300), Carrasco was found dead. Investigators suspected that the kidnapping was committed by relatives of the victim, but could not find enough evidence to make an arrest.

Police have arrested two other people and are searching for three others.

The city’s Attorney General’s Office said today there was evidence that Ronquillo’s murder was related to a personal debt he owed.

Ronquillo, who was a student at Pedregal University, was kidnapped on June 4 as he was leaving the school. After his parents received a phone call demanding a ransom, a 500,000-peso payment was delivered by Ronquillo’s cousin, identified as Osvaldo “F,” to an unknown individual in a grey Ford Topaz. On June 8, Ronquillo was found dead in Xochimilco.

Source: El Universal (sp), Milenio (sp), La Jornada (sp), La Silla Rota (sp)