diff --git a/pkg/detectors/fetchrss/fetchrss.go b/pkg/detectors/fetchrss/fetchrss.go
index 64f9af85bbea..ff6d319ba0ea 100644
--- a/pkg/detectors/fetchrss/fetchrss.go
+++ b/pkg/detectors/fetchrss/fetchrss.go
@@ -2,26 +2,30 @@ package fetchrss
 
 import (
 	"context"
-	regexp "github.com/wasilibs/go-re2"
+	"encoding/json"
+	"fmt"
 	"io"
 	"net/http"
-	"strings"
+
+	regexp "github.com/wasilibs/go-re2"
 
 	"github.com/trufflesecurity/trufflehog/v3/pkg/common"
 	"github.com/trufflesecurity/trufflehog/v3/pkg/detectors"
 	"github.com/trufflesecurity/trufflehog/v3/pkg/pb/detectorspb"
 )
 
-type Scanner struct{}
+type Scanner struct {
+	client *http.Client
+}
 
 // Ensure the Scanner satisfies the interface at compile time.
 var _ detectors.Detector = (*Scanner)(nil)
 
 var (
-	client = common.SaneHttpClient()
+	defaultClient = common.SaneHttpClient()
 
 	// Make sure that your group is surrounded in boundary characters such as below to reduce false positives.
-	keyPat = regexp.MustCompile(detectors.PrefixRegex([]string{"fetchrss"}) + `\b([0-9A-Za-z.]{40})\b`)
+	keyPat = regexp.MustCompile(detectors.PrefixRegex([]string{"fetchrss"}) + `\b([a-zA-Z0-9.]{40})\b`)
 )
 
 // Keywords are used for efficiently pre-filtering chunks.
@@ -34,37 +38,26 @@ func (s Scanner) Keywords() []string {
 func (s Scanner) FromData(ctx context.Context, verify bool, data []byte) (results []detectors.Result, err error) {
 	dataStr := string(data)
 
-	matches := keyPat.FindAllStringSubmatch(dataStr, -1)
-
-	for _, match := range matches {
-		if len(match) != 2 {
-			continue
-		}
-		resMatch := strings.TrimSpace(match[1])
+	uniqueMatches := make(map[string]struct{})
+	for _, match := range keyPat.FindAllStringSubmatch(dataStr, -1) {
+		uniqueMatches[match[1]] = struct{}{}
+	}
 
+	for token := range uniqueMatches {
 		s1 := detectors.Result{
 			DetectorType: detectorspb.DetectorType_Fetchrss,
-			Raw:          []byte(resMatch),
+			Raw:          []byte(token),
 		}
 
 		if verify {
-			req, err := http.NewRequestWithContext(ctx, "GET", "https://fetchrss.com/api/v1/feed/list?auth="+resMatch, nil)
-			if err != nil {
-				continue
-			}
-			res, err := client.Do(req)
-			if err == nil {
-				defer res.Body.Close()
-				bodyBytes, err := io.ReadAll(res.Body)
-				if err != nil {
-					continue
-				}
-				body := string(bodyBytes)
-
-				if !strings.Contains(body, "Not authorised") {
-					s1.Verified = true
-				}
+			client := s.client
+			if client == nil {
+				client = defaultClient
 			}
+
+			verified, verificationErr := verifyToken(ctx, client, token)
+			s1.Verified = verified
+			s1.SetVerificationError(verificationErr)
 		}
 
 		results = append(results, s1)
@@ -73,6 +66,51 @@ func (s Scanner) FromData(ctx context.Context, verify bool, data []byte) (result
 	return results, nil
 }
 
+func verifyToken(ctx context.Context, client *http.Client, token string) (bool, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, "https://fetchrss.com/api/v1/feed/list?auth="+token, nil)
+	if err != nil {
+		return false, err
+	}
+
+	res, err := client.Do(req)
+	if err != nil {
+		return false, err
+	}
+	defer func() {
+		_, _ = io.Copy(io.Discard, res.Body)
+		_ = res.Body.Close()
+	}()
+
+	// The API seems to always return a 200 status code.
+	// See: https://fetchrss.com/developers
+	if res.StatusCode != http.StatusOK {
+		return false, fmt.Errorf("unexpected HTTP response status %d", res.StatusCode)
+	}
+
+	var apiRes response
+	if err := json.NewDecoder(res.Body).Decode(&apiRes); err != nil {
+		return false, err
+	}
+
+	if apiRes.Success {
+		// The key is valid.
+		return true, nil
+	} else if apiRes.Error.Code == 401 {
+		// The key is invalid.
+		return false, nil
+	} else {
+		return false, fmt.Errorf("unexpected error: [code=%d, message=%s]", apiRes.Error.Code, apiRes.Error.Message)
+	}
+}
+
+type response struct {
+	Success bool `json:"success"`
+	Error   struct {
+		Message string `json:"message"`
+		Code    int    `json:"code"`
+	} `json:"error"`
+}
+
 func (s Scanner) Type() detectorspb.DetectorType {
 	return detectorspb.DetectorType_Fetchrss
 }