The phrase "about to murder" is correct and usable in written English.
It can be used in contexts where someone is on the verge of committing an act of murder or is expressing an intention to do so imminently.
Example: "He stood there, knife in hand, looking at his target, clearly about to murder."
Alternatives: "on the verge of killing" or "ready to commit murder."
She bravely discouraged a madman about to murder her by reminding him "Then you'll get hung," and paraded for women's rights.
But when people call you, you have blood on the carpet or you're about to murder yourself or you're watching a porno movie.
I arrived home in 1999, unaware that my papa was about to murder an American over a stake in a nutria farm… My best buddy in Russia is a former American and successful businessman I like to call Alyosha-Bob.
We're thrust into a gothic world where the wicked Miraz, leader of the Telmarines, has usurped the throne of Narnia and is about to murder the rightful ruler, Prince Caspian.
I arrived back here in July of 1999, ostensibly to visit my beloved papa for the summer, completely unaware that he was about to murder an Oklahoma businessman over a ten-per-cent stake in a nutria farm.
Sorry, what was that you said about... "Oh, people say how can you say that, but I say, how can you support Bush when he is about to murder so many Iraqis?
Say what you want about Heathcliff, but he is (a) sexy to a select number of people and (b) talks about wanting to murder people all the time.
David Cameron said companies had a "social responsibility" to act on terrorist material posted online after the report detailed how Michael Adebowale, one of two men convicted of Mr Rigby's murder, spoke on Facebook about wanting to murder a soldier.
Instead, they go after people who are about to commit murder, swooping down to stop them in the nick of time.
Titian lived in Venice, where Shakespeare set his tragedy Othello, and like Othello, the husband in the painting is so obsessively jealous he is about to commit murder.
Colonel Qaddafi has left no question about his willingness to murder civilians.
