DENVER (CBS4)– Denver Mayor Michael Hancock said the two young children killed in a hit and run crash should always be remembered.

In March, Ah Zet Khan, 6, and his brother Za May Khan, 8, were struck and killed at the corner of 14th and Yosemite.

They were crossing the street with their mother, Zamar Bee. She survived but has critical injuries.

A memorial sign was placed at that intersection on Friday.

Family, friends and the boys’ mother were there for the ceremony.

Hancock led the crowd in reading their names and then spoke directly to the hit and run driver.

“Someone knows what happened here to end these two lives tragically. We implore you, we encourage you, we demand that you demonstrate the courage to come forward and help this family, this mother have closure,” said Hancock.

That driver has not been arrested. Surveillance video at the scene showed a white or silver SUV driving away from the crash.

Police said they continue to follow up on leads but are searching for more information.