The man who allegedly “pinged” Anti-Gang Unit section commander Lt Col Charl Kinnear’s phone more than 2,000 times was taken in for questioning by a team of crack detectives in Johannesburg earlier this week.

According to a source, a 39-year-old man from Springs, on Gauteng's East Rand, is also believed to have tracked the phones of Cape Town lawyer William Booth, who was himself the target in a shooting in Higovale on April 9.

He was also allegedly pinging the phones of another high-ranking Anti-Gang Unit member, and an underworld boss who is a rival of another alleged underworld leader, Nafiz Modack.

In March, Modack endorsed the services of the man on his Facebook page, saying that “all Johannesburg debt collections” needed to go through him.

The man cannot be named until he appears in court.

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When contacted by SowetanLIVE sister publication TimesLIVE on Wednesday night, Hawks spokesman Brig Hangwani Mulaudzi would not confirm or deny any arrests related to the case.

"We are treating this matter with the sensitivity it deserves. We will formally announce any developments at the right time," he said via text message.

Kinnear was gunned down while waiting for his son in his car outside his home in Bishop Lavis on Friday.

He was a detective head of an Anti-Gang Unit team, and was working on several high-level cases.

Most recently, Kinnear was part of the large-scale investigation into the Central Firearms Registry, where alleged corruption at several police stations across the country apparently helped high-profile gang bosses secure firearms for themselves and their extended circle of friends, family, and bodyguards.