[10] Rappler investigation through the Freedom of Information, was able to obtain from the Malacanang Records Office of an official documentation contracting Yang as an Economic Adviser.

Yang denied this and explained that he was sought by Pharmally executives, Lin Wei Xiong and Mohit Dargani, and provided assistance to meet President Duterte in Davao.

"[23] Yang's and his associate Lin Wei Xiong operated the Xionwei Technology Co. Ltd. in Bacoor, Cavite in August 2016, or two months into the Duterte presidency.

[30] In August 2017, a police anti-narcotics intelligence report made by Col. Eduardo Acierto mentioned Michael Yang and his associate Lin Wei Xiong (also known as Allan Lim) as the operator of a number of methamphetamine laboratories around Mindanao.

"[31][32] The said report was then furnished to Philippine National Police Chief Ronald "Bato" dela Rosa, Philippine Drug Enforcement Agency (PDEA) Director Aaron Aquino, Police Deputy Director General Camilo Cascolan, as well as to Senator Richard Gordon, Executive Secretary Salvador Medialdea, and former Special Assistant to the President Christopher “Bong” Go.

In a twist of events, on October 2018 Duterte cleared Yang, and tagged Acierto as one of the police officials who was involved in the illegal drug trade, and implicated him in the PhP 11 billion shabu haul concealed in magnetic lifters at the Manila International Container Port and in Cavite.

[34][35] In November 2021, former Davao police investigator and self-confessed member of the Duterte Death Squad (DDS), Arturo Lascanas, gave an affidavit to the International Criminal Court (ICC), and pointed that Chinese businessmen who were close to then Mayor Rodrigo Duterte, Charlie Tan, Sammy Uy, and Michael Yang, were involved in drugs smuggling in Mindanao.

Tan was previously named by former Senator Panfilo Lacson of being part of the "Davao Group" along with presidential son and Congressman Paolo "Polong" Duterte.

Lascanas also disclosed in his affidavit that former PNP Chief Dela Rosa, as well as PDEA Director Wilkins Villanueva, were "enablers" of the illegal drug trade.

[38] During the investigation, the warehouse was identified to be owned by Empire 999 Realty Corporation, and the land where it was built was purchased from the brother of the former Mayor of Mexico, Pampanga, Teddy Tumang.

Guban mentioned that it was his team that intercepted part of the PhP 11-billion drug haul hidden in magnetic lifters at the Manila International Container Port.

He disclosed that prior to the Senate Investigation on the drug haul in September 2018, he was approached by journalist Paul Gutierrez who was working as a staff of the Department of Environment and Natural Resources (DENR) Undersecretary Benny Antiporda.

Gutierrez, who is currently the Undersecretary and Executive Director of Presidential Task Force on Media Security (PTFoMS), and Antiporda denied the claims of Guban.

[44][45][46] According to Arturo Lascanas' affidavit to the ICC the state-sponsored killings under the Davao Death Squad (DDS) was primarily targeting individuals who could potentially reveal Yang's drug trade and how Duterte gave protection.

[47][48] Lascanas would also disclose that the DDS was headed by Police Captains Royina Garma and Edilberto Leonardo, and its operational funds sourced from the city's peace & order, and intelligence budget.

[49][50] Lascanas would also claim that then Mayor Duterte in person gave him instructions to kidnap Philip Lam in front of Michael Yang for the amount of PhP 350,000.

"[51] On September 15, 2022 the Philippine National Police Anti-Kidnapping Force named three POGOs involved in kidnapping incidents during a Senate Hearing by the Committee on Public Order and Dangerous Drugs.

These POGOs were Xionwei Technologies and LY Ground Admin in Cavite, and Lucky South 99 in Pampanga, all of whom were allegedly connected to Michael Yang.