In Amsterdam’s Red Light District, the hologram of a women sits behind a window. She looks out at passers-by, then appears to knock on the window and breathe on the glass. The glass seemingly fogs up, and the word “help” appears.

This hologram is modeled on Bernadett “Betty” Szabó, a 19-year-old Hungarian sex worker who was murdered in the Dutch capital in 2009. Now, more than 15 years after her death, police are hoping to uncover new information about her killing.

Szabó grew up in poverty in the Hungarian city of Nyíregyháza, before moving to Amsterdam when she was 18 years old and beginning work as a prostitute, Dutch police said in a statement. She quickly became pregnant, but continued to work throughout her pregnancy, giving birth to her son in November 2008.

Three months later, she was found dead in her workroom, lying in a pool of blood. She had been stabbed “dozens of times,” Dutch police said.

Despite a large-scale investigation, in which police monitored CCTV, interviewed witnesses, and combed over the crime scene, the case eventually became cold.

The holographic representation of Szabó was created to reach those who may know something about her murder but did not come forward when it happened.

“It is difficult to determine what it takes to get possible witnesses in this case to share their information with us,” Benjamin van Gogh, coordinator of the Amsterdam Wanted and Missing Persons Team, said in the statement.

“Betty’s hologram may create a certain connection with her and thus convince a person to come forward. In this type of case, we always try to put a face on a victim, so that informants know who they’re doing it for, and the hologram is a way of taking this a step further.”

The police force discussed the campaign with Szabó’s family, van Gogh said, adding that it is “committed to doing this with dignity and with the clear purpose of achieving some form of justice for Betty by finding her murderer or murderers.”

“Research shows that people who commit a crime like this usually tell multiple people – 2.2 persons to be exact – what they have done. This means that there must be people that know more about Betty’s death,” she said.

The reward for information related to the case has been raised to €30,000 (around $32,160). Amsterdam gets tourists from around the world, Roovers pointed out, so police are urging those who visited the city in February 2009 to get in touch if they know anything more about the case.