She had previously praised her brother in a March birthday post when he turned 20 for his ‘life’.
Sharing a photo of herself near Alex’s, she wrote on Instagram: “I thank God for your life and do not take you for granted!! I love you very much and I’m so proud of everything you are doing for yourself.
“You are a go getter and I pray God blesses every step forward you are making.”
No arrest yet
Coming at a time when there is a global call for justice for victims of violence and brutality, Mr Kareem’s mourners are demanding the arrest of those involved in the killing.
The police are appealing for information about a white Range Rover driven by his killers which was found burned out three miles away in Ealing but they said no arrests had yet been made.
Police Chief Inspector, Wayne Jolley, said: “We are determined to bring those responsible for this unnecessary and terrifying violence to justice.
“We continue to appeal for witnesses who may have seen or heard what happened to come forward.
“The white Range Rover seen in the area and later found burned out is also a key part of the investigation.”