Bucharest newspapers said that Western countries might have signalled to the Romanian government that Mr Magureanu's departure would improve Romania's chances of joining Nato in the alliance's first wave of enlargement in 1999. As a former officer in the Securitate, the Communist-era predecessor of his own Romanian Intelligence Service (SRI), Mr Magureanu, 56, might not have been an acceptable figure to Nato, the papers suggested.
When asked on Bucharest radio whether there was any truth to these reports, the spy chief's spokesman, Nicolae Ulieru, said: "Probably, yes." However, he defended the SRI, which was set up in 1990 by the former president, Ion Iliescu, as an institution that respected democracy and had never broken the law.
Mr Magureanu was a member of the self-styled jury that condemned the dictators Nicolae and Elena Ceausescu to death on Christmas Day 1989. Despite coming under attack for supposedly allowing Securitate methods to persist in the SRI, he kept his job while all other leading participants in the 1989 revolution fell from grace.
Before last November's elections, in which Romania's liberal opposition came to power for the first time since 1989, Mr Magureanu said that he intended to resign regardless of the vote's outcome. However, it remains possible that there is more to his announcement this week than meets the eye.
Just three days before he handed in his resignation, the SRI publicly expressed fury at a Romanian newspaper, Jurnalul National, for publishing an article by a former Securitate boss and defector to the West, Ion Pacepa. This article, originally published in the Washington Times, accused Mr Magureanu and the SRI of abusing their power and undermining democracy.
The SRI rejected Mr Pacepa's accusations and pointed out that he had loyally served Ceausescu as head of Romanian foreign espionage for many years before his defection. Mr Pacepa is perhaps best known in the West for his lurid memoirs, Red Horizons, which portray Ceausescu's Romania as an almost surreal world of corruption, depravity and violence.
The accuracy of Pacepa's book has since come under question. However, his knowledge of security matters lends more weight to his account of what was going on in the SRI under Mr Magureanu.
Before last November's elections Western governments were unhappy with the degree of democratic change in Romania. Since then, relations have warmed, but perhaps not enough to guarantee Romanian entry into Nato in the first wave - with or without Mr Magureanu's resignation.