News of the arrest of Raul Salinas, long accused by opponents of making hundreds of millions of dollars in privatisations pushed through by his brother, stunned a nation already in shock over deepening political and economic crisis. It immediately raised the question of whether Carlos Salinas de Gortari himself may have had any involvement in the 28 September murder of Mr Ruiz Massieu outside a Mexico City hotel.
A lone gunman was arrested at the time but his statements and later investigations quickly pointed to the likelihood that he had fallen victim to an internal power struggle in the PRI between hardliners and reformers. Mr Ruiz Massieu was considered a reformer. Carlos Salinas publicly billed himself as such, but opposition leaders and many Mexicans always doubted this.
Despite his public speeches promising "abertura" (opening up), he was said to be much harder line in private and had close ties with the party's so-called dinosaurs, the older generation firmly opposed to any change that would remove their power base or threaten their wealth.
Events since he stepped down on 1 December have also suggested Mr Salinas deliberately hid a growing financial crisis now threatening his hand-picked successor Ernesto Zedillo. The arrest of Raul Salinas, the growing clouds over his brother and the largely-inept leadership of Mr Zedillo since 1 December have threatened to shatter the PRI, which has ruled non-stop since 1929, and led to rumours of a peaceful coup d'tat to replace Mr Zedillo.
The arrest followed a dramatic weekend during which Mexico's attorney- general announced that last year's other key murder in Mexico, that of PRI presidential candidate Luis Donaldo Colosio in March, was the result of a plot and involved local PRI militants in the city of Tijuana. The Attorney-General, Antonio Lozano, hinted that Mr Salinas's government was guilty of covering up the plot, trying to blame the killing on a lone deranged gunman. That led Mr Salinas to make an unprecedented television speech yesterday - before the arrest of his brother - denying a cover- up in the Colosio case.
Ruiz Massieu's murder plunged Mexico into turmoil. Foreign investors, already unnerved by Colosio's murder six months earlier, fled the country in droves, helping to spark a devaluation of the national currency and a dive into recession.
Meanwhile, according to 95 per cent of those who took part in an unofficial nationwide "referendum" last weekend, Mr Salinas should be prosecuted for causing Mexico's economic crisis.
The poll was organised by the Civic Alliance, a respected independent group best known for monitoring the country's elections, at almost 5,000 "polling stations".Of around half a million Mexicans who took part, nearly 80 per cent said the congress should reject a US-led $50bn (£32bn) bailout package as "a breach of national sovereignty" since it imposes tough conditions on Mexico.Reuse content