POLICE investigating the murder of a university student are urging an anonymous caller who may have vital information to contact them again.

The man called Crimestoppers on March 1, the day after BBC’s Crimewatch show broadcast an appeal for information on the killing of 24-year-old Samuel Guidera.

Mr Guidera, who lived in Avenue Road, Penge, died after being stabbed in the heart in Newlands Park, Sydenham, on February 12.

Detective Chief Inspector Laurence Smith, who is leading the investigation for the Met Police, is urging the anonymous caller or anyone who knows who he is to get in touch.

He said: "We believe that this man may hold information that is very important to this investigation and may enable us to find Samuel's killer.

“I would ask this person to consider contacting us direct. We can protect their anonymity but we do need people to come forward with information."

Police are also offering a reward of up to £20,000 for information leading to the identification, arrest and prosecution of Mr Guidera’s murderer.

Mr Guidera was found collapsed in the street at 9.54pm, shortly after leaving Penge East rail station. His wallet was taken during the attack.

In March detectives released CCTV footage of around 40 people who were in the area of Penge East rail station at the time Mr Guidera was killed, asking them to contact police.

So far 20 people have come forward, and DCI Smith urged the rest to do so, saying: “They may hold information that helps us piece together the events leading up to Sam's death.”

Mr Guidera was studying history and politics at University of Greenwich and hoped to become a secondary school teacher.

If you have information, call the Met on 020 8345 3734, or Crimestoppers anonymously on 0800 555 111.

To see the CCTV footage, search for Samuel Guidera on YouTube.