During his time as mayor of Buena Fe, Mendoza received various accusations for alleged acts of corruption and illicit enrichment. The accusations were made by a group of citizens led by Jorge Mogrovejo Velasco, leader of the Democratic People's Movement, who filed complaints against Mendoza with the State Comptroller General, the Internal Revenue Service and the Commission for Civic Control of Corruption in which it emphasized how Mendoza, who came from a middle-class family and had a small personal wealth at the time he began his term as mayor, had become the owner of haciendas in the provinces of Los Ríos, Pichincha and Esmeraldas; mansions in Buena Fe, Salinas and Miami; and several luxury vehicles, one of them valued at US$150,000.[2]
Several of the denouncers received death threats and two of them suffered a failed attack in June 2003 when unknown persons shot at a vehicle in which they were moving. A group of inspectors from the Comptroller's Office arrived at the municipality in mid-August to begin an audit of Mendoza's management, but the mayor prevented them from carrying out the evaluation. On 26 August 2003, Mogrovejo was murdered by unknown persons who fired seven shots at him while he was going to his home. Mogrovejo's wife held Mendoza responsible for the attack and recounted the death threats that both Mogrovejo and his relatives had received after initiating the allegations of corruption.[3][4] Mendoza categorically denied the allegations.[2]
The Commission for Civic Control of Corruption found indications of criminal responsibility against Mendoza for illicit enrichment, but the case was filed.[5]
In the 2006 legislative elections, Mendoza was elected national deputy representing the Los Ríos Province by the Ecuadorian Roldosista Party,[5] but he was dismissed from office along with the rest of the National Congress in November of the following year when the Ecuadorian Constituent Assembly commenced.[6]
In 2017, Mendoza was elected national assemblyman representing Los Ríos by the alliance between the CREO and SUMA movements.[7] At the end of 2018 he resigned from office to run as a candidate for mayor of Los Ríos in the 2019 sectional elections,[8] but lost to Johnny Terán, whom Mendoza accused of having committed electoral fraud.[1]
Shortly before his death, Mendoza registered as a candidate for assembly in the 2021 legislative elections for the Avanza party.[1] In December 2020, he filed a complaint against Terán for allegedly misusing prefectural assets to promote the campaign his son's election to the National Assembly, for which he presented videos, audio recordings and photographs as evidence.[9]