In an emotional tweet the author said she "can't stop crying" over the death of 22-year-old Luis Vielma.
The tweet prompted a number of tributes, some from people who knew Vielma.
Omar Mateen, the man identified by officials as the gunman, stormed a gay bar in the early hours of Sunday morning. Following a three-hour hostage situation, he was shot by police.
The gunman’s father told US media that his son got angry when he recently saw two men kissing in Miami. He said that might be related to the attack.
Mateen was armed with a powerful assault-type rifle and handgun when he sprayed revellers with bullets at the popular gay nightclub, Pulse, in Orlando, Florida.
The FBI have said the 29-year-old killer born in New York was an American citizen who legally purchased two firearms within the last week before murdering at least 50 people.
Edward Sotomayor Jr, 34, Stanley Almodovar III, 23, Luis Omar Ocasio-Capo, 20, and Juan Ramon Guerrero, 22, were among the first victims to be named.
Peter O. Gonzalez-Cruz, 22, and Eric Ivan Ortiz-Rivera 36, and Luis S Vielma, 22, have since been added to the list of deceased.
More than 300 people were inside the building at the time of the attack - 53 people are also in hospital, with most in a critical condition.
It was the biggest killing of LGBT people in the West since the Holocaust as pointed out by Owen Jones.
He said: “People rationalise their hatred. This guy, apparently, according to his dad, saw two men kissing and he was repulsed by it.
“And people know this who are gay, that there are people out there who are sickened and repulsed by our very existence and this guy, however he dresses up his bigotry and hatred, is somebody who hates gays.
“He hates LGBT people and he had a gun... and he used that to murder LGBT people.
“But can we just be clear, because you say it’s lunatics and the rest of it, if he went into a synagogue and killed innocent Jewish people... we call it out for what it is.
“This person is a homophobic terrorist, whatever else he is,” adding: “At the end of the day this was a homophobic crime, as well as terrorism and it has to be called out.”