MANILA, March 12 (Reuters) - The Philippines' justice department has dismissed complaints against several high-profile drugs trade suspects because of weak evidence, according to documents reviewed by Reuters on Monday.In his bloody war on drugs, President Rodrigo Duterte had publicly named and shamed provincial politicians and businessmen as "drug lords" controlling the narcotics trade in the Southeast Asian nation."We are mindful of the zealous intention of the complainant to eliminate the illegal drug menace prevalent in our country today, and it is public knowledge that this fight has taken numerous lives," a Department of Justice panel said in a ruling seen by Reuters, dated Dec. 20 last year, but not made public.But law enforcement agencies should "gather more concrete and competent evidence proving that respondents and other individuals are indeed involved in illegal drugs trade," it added.The justice secretary was not immediately available for comment on Monday.The collapse of the cases will be a blow to Duterte, who has been criticised by political opponents and human rights groups for primarily targeting small-time users and dealers in a brutal campaign that has left drugs kingpins largely untouched.Among the 22 people cleared were businessman Peter Go Lim and Kerwin Espinosa, who was arrested by Abu Dhabi police in October 2016. Espinosa's father, Rolando, was mayor of Albuera town in central Leyte province and surrendered in August 2016 to answer drugs charges.He was killed three months later, in what police said was a shootout at a prison where he was detained. Activists and the opposition say the circumstances of his death were highly suspicious.Since Duterte took office in June 2016, 4,021 people have been killed in what police call legitimate operations against "drug personalities" they say ended in shootouts. Police have blamed vigilantes for about 2,300 other drug-related homicides.