Prosecutor's office says one assailant identified as man who raped one of Friday's victims nine years ago.
After gunmen killed 11 members of the same family in a remote mountain village in Mexico on Friday, authorities said the motive was "personal conflicts".
The pre-dawn attack occurred in El Mirador, a community in central Puebla state. The gunmen broke into the family's house in a mountainous area known as Sierra Negra and started shooting. They also used knives. The victims were five women, four men and two girls.
Two other girls were wounded and hospitalised.
Witnesses identified two assailants and recognised one of them as the man who allegedly raped one of the dead women nine years ago, resulting in the birth of a boy, according to the state prosecutor's office.
The woman's current partner, who was killed, was stabbed several times and had "more wounds than the other" victims, the office said in a statement.
Two of the witnesses have been placed under police protection.
The prosecutor's office said the gunmen "arrived on foot where the family was located, fired several times and left on foot." The two assailants reportedly fled towards the neighboring state of Oaxaca.
Authorities in both states are searching for them. The hamlet is so remote that it is only accessible on foot.
Act of revenge
"It was an act of revenge," said Vicente Lopez de la Vega, the mayor of Coxcatlan which is the municipality that oversees El Mirador.
"To kill 11 people like that, you don't have feelings. It's alarming."
An official at the prosecutor's office had earlier said authorities were investigating whether the killings were related to organised crime or a family dispute.
"It's a community in harmony, but things change. There's immigration. Many go north of the country and to the United States. Sometimes when people come back the harmony is lost," said Lopez de la Vega .
Puebla is a relatively quiet area with rare occurrences of drug-related violence. However, the situation has changed in recent months.
In April, four bodies were found inside a burnt car near Veracruz, an eastern state known for its murders and disappearances linked to drug cartels. That same day, three other bodies were found in the same area near a facility of state-run oil firm Pemex.
In May, four people were killed after gunmen opened fire in the village of La Purisima where rival gangs seek to control illegal pipeline taps.