The most famous example is in the 1960’s: the Cuba of Fidel Castro turned dictatorial after he let the Soviet Union take over training domestic policing and his secret service (in exchange for buying up his sugar an most of Cuban cigars; see Tad Szulcs biography of Fidel).
But also in the 1980’s the regime of Robert Mugabe over Zimbabwe appeared to start out in 1980 as a better alternative to South African Apartheid, but there the instant imposition and eternal prolongation of the State of Emergency, the role of the North Korean (guaranteed Stalinist) military training mission, their Zimbabwean Fifth Brigade pupils and their Gukurahundi 1983-7 offensive suppressing Nkomo’s democratic opposition, disillusioned many supporters very fast. When in 1987 the presidency got real executive powers and Nkomo’s party was absorbed in Mugabe’s regime, things turned sour “for keeps”, resulting in misrule, murderous peasant evictions, clobbering opposition leaders to a pulp, and hyperinflation.
The 1979 Sandinista revolt in Nicaragua under Daniel Ortega kept on the democratic, progressive path during the 1980’s, but after losing the 1990’s election Ortega forced social democratic party veterans like Ernesto Cardenal and novelist Sergio Ramírez out, becoming more autocratic. Ortega and his clique in 1990 kept the nationalized enterprises as their property, and after returning to government in 2006, Ortega was illegally re-elected president in 2011. Ortega, having fought the Roman Catholic hierarchy up to 1990, co-operated with the orthodox wing of that church (archbishop Obando) after returning to government in 2006, banning abortion in all circumstances (his main campaign issue and that of the “liberals”. Human Rights Watch since reported that bleeding pregnant women don’t get treated for fear of breaking that ban, and the Health Ministry ignores complaints about pre- and postnatal care.