Luis Carlos Dominguez, a longtime friend and former business associate of English-born Berry, said he was raised in Venezuela and ran a travel agency.
"He knew Venezuela a lot better than many Venezuelans," said Dominguez, describing the slain couple as people "who really loved the country," had a good relationship despite their divorce and made it a point to vacation together.
"They weren't together," he said. "But they were very attached for the benefit of their daughter."
Maduro lamented "the loss of a very spiritual young woman" actively involved in various charities, including one that helped placed mentally disabled teens in jobs.
One top opposition leader, Leopoldo Lopez, blamed Spear's death squarely on the government: "This government is an accomplice of armed groups, judicial corruption, arms trafficking," he tweeted.
In response to the killings, Maduro announced that he would convene a security meeting on Wednesday that had originally been scheduled for the end of January. It is to bring together state governors and mayors of Venezuela's 79 most dangerous cities.
