Heath Ledger's father appalled by Dark Knight Rises screening shooting

Heath Ledger's father was horrified to read reports suggesting the alleged gunman who killed 12 people at a screening of The Dark Knight Rises modeled himself on his late son's Batman character The Joker, branding the tragedy "diabolical".

Twelve people were killed and 59 injured when suspect James Holmes opened fire in a packed Colorado movie theater.

It has been reported that Holmes called himself The Joker - the crazed villain played by Ledger in 2008's The Dark Knight - and even dyed his hair red in homage to the clown character, and Kim Ledger has been left disturbed by the news.

He has also called for a tightening of firearms laws and tells Australia's Herald Sun, "It's terrible - the whole circumstances. It's diabolical. I am appalled. The guy's obviously a nut case. He has obviously lost it.

"I think what America should be doing is restricting the availability of ammunition or revisiting their gun laws - that's what they should be doing.

"We can't blame Heath or the character. It's (The Joker) fictitious. I don't know what this does to the character. I think that's the least of my worries."

Ledger, who died in 2008 during post-production of The Dark Knight, won a posthumous Academy Award for his performance.