Though it remained unclear how Crump, who lived with his mother and grandmother but often stayed with girlfriends and friends, wound up at the construction site, police do not believe he was abducted, Clark said.
Detectives were still trying to determine a motive for the killing of a young man who did not have a police record. Crump was shot 10 to 12 times in the head and face around 5:30 a.m., and at one point had been on his knees.
Crump's family was planning to hold a vigil for the teen, who they said was popular and had charisma, and had been working at Wendy's for just two weeks.
"He had a million friends and a big family that loved him," his mother, Sherron Kaba, 39, said Tuesday. "I know everybody loved him. Everybody always said he had an infectious smile and it melted their heart."
The manner in which her son was killed was especially painful for the Northeast Philadelphia resident.
"I don't want to talk about what happened," she said. "I believe in God and love my son and believe he is in heaven. That is how I'm dealing with this the best I can."
On Twitter, Crump's posts would alternate between gangsta-rap posturing and religious devotion.
One friend described him as someone who dreamed of making it as an entrepreneur.
Kaba said Crump was a 2012 graduate of George Washington High School, which is near the crime scene. Crump loved playing basketball and was a big fan of LeBron James, Kaba said.
Crump was also a fan of hip-hop mogul Jay Z, she said.
"We as parents really need to take a stand and come out and embrace our kids," Kaba said. "That's why I hurt. My life was devoted to Daquan."
Crump's grandmother Reva Moore said he "was very positive. He was a typical 19-year-old."
Contact Sulaiman Abdur-Rahman at firstname.lastname@example.org, or follow on Twitter @sabdurr.