Police are searching for four more suspects in the murders of former Miss Venezuela Monica Spear and her husband, while seven others already in custody are set to be arraigned for the crime, Venezuelan authorities said Thursday.

The director of the investigative police, Jose Sierralta, said that they are conducting raids in the central and western part of the country to attempt to capture these four people.

"Up to now, the investigation shows that these other four individuals undertook the act with the aim of committing robbery," he said.

Sierralta added to the information supplied a little earlier by Justice Minister Miguel Rodriguez, who had said that two other people were involved in Monday's double-murder, which has caused great consternation and outrage around the country.

The seven people arrested on Wednesday - four men, a woman and two teenagers - were due to be arraigned in connection with the deaths of Spear, 29, and her husband Thomas Henry Berry, 39.

Four of the seven "actively" participated in the assault, Rodriguez said

"Two of them got items obtained during the robbery, which shows that the motive for the incident was robbery," he said.

One of the seven people in custody has been identified as the ringleader who incited the rest to action, "the one who gives them the drugs, gives them the weapons and orders them to commit this type of crime," the minister said.

Spear and her husband were shot to death by robbers after their vehicle suffered mechanical problems on a highway in Carabobo state and they pulled over to await help.

The couple's 5-year-old daughter was wounded.

After the crime, President Nicolas Maduro met on Wednesday with mayors and governors, including opposition leader Henrique Capriles, who is the governor of the state of Miranda, to seek their cooperation in the fight against crime.

Venezuela, a nation of roughly 29 million people, experienced 39 murders per 100,000 residents in 2013, according to official statistics, but the independent Venezuelan Violence Observatory estimates the homicide rate was actually 79 per 100,000. EFE