Two men and a woman are accused of killing a young mum – whose three-year-old child was found sitting next to her dead body – before shooting dead a cop with his service firearm when he stopped them in the victim’s car.

The victim, identified as Teresa A.V. aged between 35 and 39 years, was killed in her home in the neighbourhood of Gran San Pedro Cholul in the city of Merida in the Mexican state of Yucatan last Friday.

Before discovering the murder, the police received a report of the suspected killers attacking a policeman on the Merida-Motul motorway at around 7.45am.

According to the news site Excelsior, the uniformed cop asked the occupants to get out of the car, later discovered to belong to the murdered mother, after stopping them for driving suspiciously.

However, the two men and woman attacked the cop and disarmed him before using his service weapon to shoot him dead, according to reports.

The cop, named as Raul Couoh Ake, 23, did not know that the occupants had allegedly murdered a woman and were fleeing in her car.

The suspects, all from the Mexican state of Mexico, escaped on public transport after reportedly killing the cop, but were detained hours later at a city station while attempting to leave the state.

The police then identified the vehicle the suspects abandoned and discovered it belonged to Teresa.

Officers arrived at Teresa’s home and found her dead body alongside the woman’s three-year-old daughter, according to reports.

Police spokesperson Saiden Ojeda called the fallen officer “a hero”, adding: “The action that cost him his life prevented a crime from going unpunished and endangering the life of a three-year-old girl, who remained next to her mother’s lifeless body.”

The police are trying to uncover the motive for the woman’s murder, adding that she had filed several complaints against her ex-partner for domestic violence in the past.

Her death is considered a femicide as the police probe continues.