(CHICAGO) Chicago Police believe three “edge weapons” were used in a bloody massacre of a family last week in Gage Park, a department spokesman said Wednesday.

Last Thursday, Maria Herminia Martinez, 32, was found shot to death in her home. Her sons, Leonardo Cruz, 13, and Alexis Cruz, 10, died of “sharp force” injuries, the Sun-Times is reporting.

The boys’ grandfather, Noe Martinez Sr., 62, also died of sharp force injuries, and his wife, Rosaura, 58, and their son, Noe Martinez Jr., 38, died of a combination of sharp and blunt force injuries, the medical examiner’s office said.

Police spokesman Anthony Guglielmi said autopsy results indicated three edge weapons — knives or other cutting instruments — were used in the slayings.

A long gun was recovered from the home, but is not thought to have been used in Maria Herminia Martinez’s shooting, Guglielmi said.

The father of the boys is traveling from Mexico to Chicago for the family’s funeral, Guglielmi said. The government of Mexico has offered its assistance in the case, if needed, he said.

Consulate official Marcelino Miranda told The Associated Press on Wednesday that the U.S. granted Manuel Armando Cruz a humanitarian visa. He was expected to arrive late Wednesday and attend Sunday funeral services. The six bodies would be buried later in Mexico.

Guglielmi added that authorities know the father wasn’t in the U.S. at the time, according to AP. He said Cruz isn’t a suspect but that authorities are speaking to everyone they can for any clues.

Police have downloaded “hours of video” taken from CTA buses and a surveillance camera on a light pole at 57th and California, Guglielmi said. They’re reviewing the video for any evidence linked to the murders, he said.

Police have not provided a possible motive for the killings, but have said they don’t think the family was randomly targeted.