Jack Coleman, the “Heroes” actor who played the father of Hayden Panettiere‘s Claire Bennet, posted an emotional tribute to his late co-star following her death this week at 36 years old.

“I’m heartbroken. I couldn’t begin to put my thoughts into words until now, and they will be inadequate,” Coleman wrote on Instagram alongside a carousel of photos of the two actors on the “Heroes” set throughout the years. “I’ve loved Hayden since day one of the pilot of ‘Heroes,’ 20 years ago, when she introduced herself by shouting ‘daddy’ and throwing her arms around me. From that day on, she called me daddio. She was Haydini, because she was a magician.”

Coleman used his tribute to express some of the ways he saw the industry negatively impact his younger co-star, including reporters who would ask her inappropriate questions when she was just a teenager.

“By 17 she was #1 on IMDB Pro. She was routinely asked obnoxious questions, mostly some version of ‘when are you going to go off the rails?’” Coleman recalled. “Today, we’d recognize those questions for the misogynistic provocations they were.”

“She was hunted. Everywhere she went, there were photographers with 300 millimeter lenses — the kind that can make even the most innocent activity look sinister,” he continued. “Once, when she came to our house, paparazzi hid in the bushes behind our yard and drove onto neighbors’ lawns. They were predatory. No one, especially a teenager, should be targeted that way.”

Coleman concluded, “Today I’m filled with sorrow and regret. And anger. But that’s for another time. Right now I want to remember an extraordinary young woman who was blessed and cursed. She was vulnerable. She felt everything. It made her a remarkable actor and susceptible to the heartache and thousand natural shocks that flesh is heir to.”

Coleman and Panettiere played central characters on “Heroes” during its original four season run on NBC from 2006 to 2010. Coleman returned for the 2015 “Reborn” miniseries. Many of Panettiere’s “Heroes” co-stars have posted tributes to her in the wake of her death. Sendhil Ramamurthy, who played Mohinder Suresh, remembered how Panettiere would stand up for mistreated background actors on set and knew every crew member’s name, for instance.

In an exclusive essay for Variety, “Heroes” creator Tim Kring praised Panettiere as a “singularly talented” actor, adding: “Hayden was a true team player, which was important for a show with a large ensemble cast. She was levelheaded beyond her years as a person, with an almost savant-like quality about her work. It wasn’t just that Hayden could learn lines with ease — it was her rare ability to find and explore the nuances of drama and humor and pathos in any scene she was in.”

Panettiere’s death is currently under investigation, but there were “not any signs of foul play or suspicious circumstances,” according to police.