Error when subclassing NSObject: "EXC_BAD_ACCESS"

I'm trying to create a class called HighscoresController which subclasses NSObject. When I call init method in the following manner, I get an error in the debugger GDB: Program received signal: "EXC_BAD_ACCESS". Does anyone have any idea why? I'm completely stumped.

// Initialize the highscores controller
_highscoresController = [[HighscoresController alloc] init];

Here's my class implementation:

#import "HighscoresController.h"
#import "Constants.h"

@implementation HighscoresController

@synthesize highscoresList = _highscoresList;

- (id) init {

    self = [super init];

    _highscoresList = [[NSMutableArray alloc] initWithCapacity:kHighscoresListLength];
    int kMyListNu开发者_运维技巧mber = 0;

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"highscores.plist"];

    if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) { // if settings file exists
        NSArray *HighscoresListOfLists = [[NSArray alloc] initWithContentsOfFile:filePath];
        _highscoresList = [HighscoresListOfLists objectAtIndex:kMyListNumber];
        [HighscoresListOfLists release];
    } else { // if no highscores file, create a new one
        NSMutableArray *array = [[NSMutableArray alloc] init];
        [array addObject:_highscoresList];
        [array writeToFile:filePath atomically:YES];
        [array release];
    }
    [_highscoresList addObject:[NSNumber numberWithFloat:0.0f]];

    return self;    
}

- (void) addScore:(float)score {
    // Implementation
}

- (BOOL) isScore:(float)score1 betterThan:(float)score2 {
    if (score1 > score2)
        return true;
    else
        return false;
}

- (BOOL) checkScoreAndAddToHighscoresList:(float)score {
    NSLog(@"%d",[_highscoresList count]);
    if ([_highscoresList count] < kHighscoresListLength) {

        [self addScore:score];
        [self saveHighscoresList];
        return true;

    } else {

        NSNumber *lowScoreNumber = [_highscoresList objectAtIndex:[_highscoresList count]-1];
        float lowScore = [lowScoreNumber floatValue];
        if ([self isScore:score betterThan:lowScore]) {

            [self addScore:score];
            [self saveHighscoresList];
            return true;

        }

    }

    return false;

}

- (void) saveHighscoresList {
    // Implementation
}

- (void) dealloc {
    [_highscoresList release];
    _highscoresList = nil;
    [super dealloc];
}

@end

This line has two problems:

_highscoresList = [HighscoresListOfLists objectAtIndex:kMyListNumber];

You lose the reference to the array you allocated earlier in the method--a memory leak.

You replace it with a reference to an object that you don't retain. Using this after the object is released is certainly causing your bad access exception.