In this case, you can. Readers will make the assumption that the people were eyewitnesses to the murder and now they are being questioned about it. But be aware that the original sentence is how it is usually reported.
"to the murder" tells what the eyewitnesses saw. "about the murder" tells what sort of questions the police asked.
The police asked the eyewitnesses to the fire about the murder, but they knew nothing about it.