As Mr Lacalle, whose ruling Blanco party is in a minority in parliament, struggled to assert his authority, the opposition clamoured for changes in the government and military, amid complaints that MPs and police commanders had received death threats.
It all began with an anonymous letter, apparently from Uruguayan police sources, alerting MPs to a joint Chilean-Uruguayan military operation behind the backs of both governments. It recounted how, in November, a Chilean biochemist on the run from the Chilean courts for human rights offences had been spirited from Argentina to Uruguay and held near Montevideo. He turned up at the local police station, explaining that he had escaped from his kidnappers, but when four Uruguayan and Chilean army officers came to collect him, the police commander handed him over. He has not been heard of since.
The biochemist, Eugenio Berrios Sagredo, worked for the notorious Chilean secret police, Dina, during the military rule of General Augusto Pinochet in the 1970s and 1980s. He had developed a version of the poison gas sarin for use in Dina assassinations, and was implicated in the murder of Orlando Letelier, a Chilean diplomat, in Washington in 1976.
The Uruguayan provincial police chief who ordered Mr Berrios' return to his captors has been sacked. But the ramifications go far beyond him. His disappearance suggests that the Condor network, a shadowy organisation set up during the 1970s by the secret police of the military regimes then running all the big Latin American countries to exchange information and even prisoners, still has a half-life, even though the military regimes have been replaced by elected governments. Whether the officers were helping Mr Berrios to escape, Odessa-style, or silencing him for good remains unclear.