Instead, they found a black bag filled with human remains, Mexico News Daily reported. Investigators said the couple were on their way to a vacant lot to dispose of the body parts.
Additional remains were found in the lot, and the BBC reported that remains were found at the couple's home and another nearby property. The body parts were kept in buckets filled with cement, as well as inside a refrigerator, authorities said.
Gómez said the couple sold body parts, but it was not clear to whom.
Spanish-language newspaper El Universal reported that Juan Carlos would lure women to the couple's home by stating he had items for sale, such as clothing, cellphones and wine. To make the women feel more comfortable going to the house, he would give them his wife's cellphone number.
Juan Carlos told investigators he would kill the women, then he and his wife would dismember the bodies into small pieces to be disposed of, El Universal reported.
He and his wife also confessed to selling the missing infant for 15,000 pesos, or about $800 U.S. The BBC reported that the baby girl, named Valentina, disappeared in September with her mother, 28-year-old Nancy Huitron.
Huitron was reported missing when she failed to pick her two older daughters up from school, the news agency said.
The two other victims identified so far were Evelyn Rojas, 29, and Arlet Olguin, 23. According to the BBC, all three women were single mothers.
Investigators were able to track down Valentina and return her safely to her grandmother. The couple who bought the baby were arrested, Mexico News Daily reported.
The motive for the slayings was not immediately known.