The reward had grown to $60,000 by Tuesday evening, King wrote on social media.
They say he was driving a red pick-up truck and wearing a black hoodie when he pulled up alongside the family and opened fire.
Barnes' killer was described as a white male in his 40s with blue eyes, according to officials.
"We got to call it what it is", he said. Donors have contributed $25,000, Merritt said. "So, I felt in my heart that's it's only right that I give back to those who are down. And I urge you, whoever did this, you know who you are, please turn yourself in now because we will be looking for you, we will locate you, we will find you". "So, I've been put in a position where I can help people, largely based on community recognition".
As an enhanced image of the gunman's truck and first sketch of his face has been released, Gonzalez said all kinds of resources are being used to find the man who killed Barnes, with assistance at the local, state and federal levels.
When Harris County police officers arrived on the scene they found Washington and her two teenage daughters wounded and her youngest daughter, Jazmine Barnes, dead. Hopkins also promised to donate his $29,000 playoff check to Barnes' family to help cover funeral costs and seek justice for her killer. Two teenagers were unharmed. The family woke up early because Washington's mother was visiting.
A reward has been posted for $100,000 for information to the whereabouts of the killer.
"We should not have to be doing any of this, but here we are", King tweeted.
Jazmine Barnes was in the back seat of her family's auto with her three siblings and mother when the driver of a red pickup truck pulled alongside the vehicle and fired inside, killing her on Sunday December 30.
'He intentionally killed my child for no reason, ' she said through tears. King asked for tips and leads.
King and Merritt have been friends for about 20 years, since their days at the historically black Morehouse College in Atlanta.
On Friday police said the sketch has led to "many potential leads" that are now being investigated.
Hopkins is next in the line of thousands of people who have pledged their support and sentiments to the family.
Four suspects were later arrested in connection with the beating, CNN affiliate WIVR reported.
Authorities said they are investigating the possibility of a hate crime and the 2017 case.
"We want to awake everyone's consciousness to this and bring more attention to it".
"We're not tone deaf to some of the concerns in our community where this could be potentially race related", Gonzalez said, explaining that road rage could be another consideration.