EXCLUSIVE: Couple Alberto Rolon and Zoraida Bartolomei, their two sons aged 9 and 7 and three dogs are all found shot dead inside their new home in Romeoville, Illinois - as heartbroken grandma says: 'They were so happy'

Police named the couple as Alberto Rolon and Zoraida Bartolomei of Concord Drive in RomeovilleThey have ruled out murder-suicide and warned that the killer remains on the loose Grandmother Lydia had spoken to her daughter just hours earlier 

The mother of a woman murdered alongside her partner and their two children in their suburban Illinois home has said she has no idea why anyone would want to kill them.

Police found the bodies of Zoraida Bartolomei, 32, her partner Alberto Rolo, and sons Adriel, nine, and Diego, seven, during a routine welfare check on Sunday night at the home in Romeoville.

All had been shot dead along with the family’s three dogs at the home on the 500 block of Concord Drive.

Police have ruled out a murder-suicide and warned that the gunman remains on the loose.

‘They were so happy, they had just bought their new house five months ago,’ said Zoraida’s mother Lydia from her home in Puerto Rico.

The home in Concord Avenue was sealed of police as they began their investigation yesterday

Romeoville Police Deputy Chief Chris Burne told reporters that the killer is on the loose

Police arrived at the scene on Sunday evening after being asked to carry out a welfare check on the family

She had spoken to her daughter shortly before her death on Saturday night as the family settled down to watch a movie, and cannot understand why they were murdered.

‘There are always people who are avaricious or jealous, but I’ve got no idea,’ she added.

A family member had asked officers from the Romeoville Police Department to carry out a welfare check on the family when one of the adults failed to turn up to work at 6am on Sunday and did not answer their phone.

Officers found a scene of carnage when they arrived at 8.40pm that evening.

Romeoville Police Deputy Chief Chris Burne revealed few details at a press conference on Monday citing the ‘sensitivity of the case and the need to protect the integrity of the investigation’.

But he was confident that none of the dead was responsible and that the gunman left the scene.

Police believe the killings took place in the Chicago suburb between 9pm on Saturday, September 16, and 5am on Sunday.

‘Due to the time that has gone by, more than 18 hours from the time we were contacted, we are not asking anybody shelter in place,’ he added.

‘We are not actively looking for anyone in the area but we do always ask our residents to have a sense of self–awareness and report anything they might see as suspicious.’

Police believe the killings took place in the Chicago suburb between 9pm on Saturday, September 16, and 5am on Sunday.

Crime scene technicians removed several brown and pink bags along with part of a window from the three-bedroom home as the investigation got underway yesterday.