The Supreme Court on Thursday tied up one loose end from the last federal election in a decision that maintained the result in Etobicoke Centre.

Former Liberal MP Borys Wrzesnewskyj had challenged the result based on the number of ballots cast by people who couldn't prove they lived in the riding. An Ontario court declared the election result null and void last spring, and Conservative MP Ted Opitz appealed that decision to the Supreme Court.

Under the Supreme Court decision, Opitz keeps his seat and Wrzesnewskyj will have to wait until the next election, set for 2015, if he wants to challenge Opitz again.

But Etobicoke Centre wasn't the only loose end remaining from May 2, 2011. Here are four lingering questions about the last federal election, plus one from the 2008 election.

1. Who is Pierre Poutine?

Last February, Postmedia revealed Elections Canada was looking into fraudulent phone calls that went out in Guelph, Ont., directing voters to the wrong polling station. It's a crime under federal election laws to interfere with someone's right to vote, and to impersonate Elections Canada.

Initially known as the "robocalls" investigation for the method of automated calls used by the perpetrator, the case also came to be known by the presumably fake name of the person who registered the cellphone from which the calls came: Pierre Poutine.

There were rumours last month that investigators were about to finish their report, but nothing public has so far come out of the investigation.

2. What happened in 234 ridings?

With intense media coverage of the robocalls, voters outside Guelph started reporting mysterious calls in other ridings. An analysis by CBC News suggested the calls were made to non-Conservative supporters. At last count, Elections Canada investigators were looking into 1,394 reports from 234 ridings. There are 308 ridings in Canada.

Chief Electoral Officer Marc Mayrand and agency spokespeople won't discuss the investigation, although Mayrand says he will report to Parliament next spring on changes that should be made for the next election.

3. Will the Federal Court overturn the result in 6 ridings?

Voters in six ridings, backed by the Council of Canadians, are challenging the election wins of their Conservative MPs. The voters are asking the Federal Court to review the evidence and decide whether to overturn the results.

They allege a pattern of voter suppression that makes the election result illegitimate in ridings where the margin of victory was small. That case won't be heard until December, a year and a half after the election. There had been a seventh seat at issue, but the applicant lived in the wrong riding to bring the challenge. Applicants must live in the riding in which they're asking for judicial review.

4. Did Intergovernmental Affairs Minister Peter Penashue spend too much?

More than a year after the election, the Conservative Party replaced Labrador MP Peter Penashue's official agent with their own chief financial officer, who notified Elections Canada that she plans to file corrections to the campaign's spending records. Penashue took a loan from a local company representing Innu communities, but still hasn't paid it back, and a local airline wrote off thousands of dollars that he owed them when the previous official agent said the campaign couldn't afford to pay the bill.

Had that airline bill been paid, the campaign would have spent 20 per cent more than it should have in a race where Penashue beat Liberal incumbent Todd Russell by 79 votes.

5. Did Dean Del Mastro, parliamentary secretary to the prime minister, spend too much in 2008?

Del Mastro, parliamentary secretary to Prime Minister Stephen Harper, had been the government's lead spokesman on the robocalls controversy until it was revealed Elections Canada is looking into his 2008 campaign spending. Court documents show an investigator for the election agency believes Del Mastro overspent his 2008 campaign limit, knew he'd spent too much and tried to cover it up.

The documents show Del Mastro paid consulting company Holinshed $21,000 from his personal chequing account. He hasn't explained what that payment was for. Del Mastro says he did not exceed his spending limit.